<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers, branch linux-6.4.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Revert "drm/amd/display: Do not set drr on pipe commit"</title>
<updated>2023-09-13T07:48:45+00:00</updated>
<author>
<name>Michel Dänzer</name>
<email>mdaenzer@redhat.com</email>
</author>
<published>2023-05-22T13:08:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e769d7975a934fd9118fc36d0592162bc01adc25'/>
<id>e769d7975a934fd9118fc36d0592162bc01adc25</id>
<content type='text'>
commit 360930985ec9f394c82ba0b235403b4a366d1560 upstream.

This reverts commit e101bf95ea87ccc03ac2f48dfc0757c6364ff3c7.

Caused a regression:

Samsung Odyssey Neo G9, running at 5120x1440@240/VRR, connected to Navi
21 via DisplayPort, blanks and the GPU hangs while starting the Steam
game Assetto Corsa Competizione (via Proton 7.0).

Example dmesg excerpt:

 amdgpu 0000:0c:00.0: [drm] ERROR [CRTC:82:crtc-0] flip_done timed out
 NMI watchdog: Watchdog detected hard LOCKUP on cpu 6
 [...]
 RIP: 0010:amdgpu_device_rreg.part.0+0x2f/0xf0 [amdgpu]
 Code: 41 54 44 8d 24 b5 00 00 00 00 55 89 f5 53 48 89 fb 4c 3b a7 60 0b 00 00 73 6a 83 e2 02 74 29 4c 03 a3 68 0b 00 00 45 8b 24 24 &lt;48&gt; 8b 43 08 0f b7 70 3e 66 90 44 89 e0 5b 5d 41 5c 31 d2 31 c9 31
 RSP: 0000:ffffb39a119dfb88 EFLAGS: 00000086
 RAX: ffffffffc0eb96a0 RBX: ffff9e7963dc0000 RCX: 0000000000007fff
 RDX: 0000000000000000 RSI: 0000000000004ff6 RDI: ffff9e7963dc0000
 RBP: 0000000000004ff6 R08: ffffb39a119dfc40 R09: 0000000000000010
 R10: ffffb39a119dfc40 R11: ffffb39a119dfc44 R12: 00000000000e05ae
 R13: 0000000000000000 R14: ffff9e7963dc0010 R15: 0000000000000000
 FS:  000000001012f6c0(0000) GS:ffff9e805eb80000(0000) knlGS:000000007fd40000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000461ca000 CR3: 00000002a8a20000 CR4: 0000000000350ee0
 Call Trace:
  &lt;TASK&gt;
  dm_read_reg_func+0x37/0xc0 [amdgpu]
  generic_reg_get2+0x22/0x60 [amdgpu]
  optc1_get_crtc_scanoutpos+0x6a/0xc0 [amdgpu]
  dc_stream_get_scanoutpos+0x74/0x90 [amdgpu]
  dm_crtc_get_scanoutpos+0x82/0xf0 [amdgpu]
  amdgpu_display_get_crtc_scanoutpos+0x91/0x190 [amdgpu]
  ? dm_read_reg_func+0x37/0xc0 [amdgpu]
  amdgpu_get_vblank_counter_kms+0xb4/0x1a0 [amdgpu]
  dm_pflip_high_irq+0x213/0x2f0 [amdgpu]
  amdgpu_dm_irq_handler+0x8a/0x200 [amdgpu]
  amdgpu_irq_dispatch+0xd4/0x220 [amdgpu]
  amdgpu_ih_process+0x7f/0x110 [amdgpu]
  amdgpu_irq_handler+0x1f/0x70 [amdgpu]
  __handle_irq_event_percpu+0x46/0x1b0
  handle_irq_event+0x34/0x80
  handle_edge_irq+0x9f/0x240
  __common_interrupt+0x66/0x110
  common_interrupt+0x5c/0xd0
  asm_common_interrupt+0x22/0x40

Reviewed-by: Aurabindo Pillai &lt;aurabindo.pillai@amd.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Michel Dänzer &lt;mdaenzer@redhat.com&gt;
Signed-off-by: Hamza Mahfooz &lt;hamza.mahfooz@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 360930985ec9f394c82ba0b235403b4a366d1560 upstream.

This reverts commit e101bf95ea87ccc03ac2f48dfc0757c6364ff3c7.

Caused a regression:

Samsung Odyssey Neo G9, running at 5120x1440@240/VRR, connected to Navi
21 via DisplayPort, blanks and the GPU hangs while starting the Steam
game Assetto Corsa Competizione (via Proton 7.0).

Example dmesg excerpt:

 amdgpu 0000:0c:00.0: [drm] ERROR [CRTC:82:crtc-0] flip_done timed out
 NMI watchdog: Watchdog detected hard LOCKUP on cpu 6
 [...]
 RIP: 0010:amdgpu_device_rreg.part.0+0x2f/0xf0 [amdgpu]
 Code: 41 54 44 8d 24 b5 00 00 00 00 55 89 f5 53 48 89 fb 4c 3b a7 60 0b 00 00 73 6a 83 e2 02 74 29 4c 03 a3 68 0b 00 00 45 8b 24 24 &lt;48&gt; 8b 43 08 0f b7 70 3e 66 90 44 89 e0 5b 5d 41 5c 31 d2 31 c9 31
 RSP: 0000:ffffb39a119dfb88 EFLAGS: 00000086
 RAX: ffffffffc0eb96a0 RBX: ffff9e7963dc0000 RCX: 0000000000007fff
 RDX: 0000000000000000 RSI: 0000000000004ff6 RDI: ffff9e7963dc0000
 RBP: 0000000000004ff6 R08: ffffb39a119dfc40 R09: 0000000000000010
 R10: ffffb39a119dfc40 R11: ffffb39a119dfc44 R12: 00000000000e05ae
 R13: 0000000000000000 R14: ffff9e7963dc0010 R15: 0000000000000000
 FS:  000000001012f6c0(0000) GS:ffff9e805eb80000(0000) knlGS:000000007fd40000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000461ca000 CR3: 00000002a8a20000 CR4: 0000000000350ee0
 Call Trace:
  &lt;TASK&gt;
  dm_read_reg_func+0x37/0xc0 [amdgpu]
  generic_reg_get2+0x22/0x60 [amdgpu]
  optc1_get_crtc_scanoutpos+0x6a/0xc0 [amdgpu]
  dc_stream_get_scanoutpos+0x74/0x90 [amdgpu]
  dm_crtc_get_scanoutpos+0x82/0xf0 [amdgpu]
  amdgpu_display_get_crtc_scanoutpos+0x91/0x190 [amdgpu]
  ? dm_read_reg_func+0x37/0xc0 [amdgpu]
  amdgpu_get_vblank_counter_kms+0xb4/0x1a0 [amdgpu]
  dm_pflip_high_irq+0x213/0x2f0 [amdgpu]
  amdgpu_dm_irq_handler+0x8a/0x200 [amdgpu]
  amdgpu_irq_dispatch+0xd4/0x220 [amdgpu]
  amdgpu_ih_process+0x7f/0x110 [amdgpu]
  amdgpu_irq_handler+0x1f/0x70 [amdgpu]
  __handle_irq_event_percpu+0x46/0x1b0
  handle_irq_event+0x34/0x80
  handle_edge_irq+0x9f/0x240
  __common_interrupt+0x66/0x110
  common_interrupt+0x5c/0xd0
  asm_common_interrupt+0x22/0x40

Reviewed-by: Aurabindo Pillai &lt;aurabindo.pillai@amd.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Michel Dänzer &lt;mdaenzer@redhat.com&gt;
Signed-off-by: Hamza Mahfooz &lt;hamza.mahfooz@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: sc16is7xx: fix regression with GPIO configuration</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Hugo Villeneuve</name>
<email>hvilleneuve@dimonoff.com</email>
</author>
<published>2023-08-07T21:45:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7e3ca33752bd999c3e2f3c67987827e921af4d5e'/>
<id>7e3ca33752bd999c3e2f3c67987827e921af4d5e</id>
<content type='text'>
[ Upstream commit 0499942928341d572a42199580433c2b0725211e ]

Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
changed the function of the GPIOs pins to act as modem control
lines without any possibility of selecting GPIO function.

As a consequence, applications that depends on GPIO lines configured
by default as GPIO pins no longer work as expected.

Also, the change to select modem control lines function was done only
for channel A of dual UART variants (752/762). This was not documented
in the log message.

Allow to specify GPIO or modem control line function in the device
tree, and for each of the ports (A or B).

Do so by using the new device-tree property named
"nxp,modem-control-line-ports" (property added in separate patch).

When registering GPIO chip controller, mask-out GPIO pins declared as
modem control lines according to this new DT property.

Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Reviewed-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Tested-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Acked-by: Rob Herring &lt;robh@kernel.org&gt;
Link: https://lore.kernel.org/r/20230807214556.540627-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 0499942928341d572a42199580433c2b0725211e ]

Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
changed the function of the GPIOs pins to act as modem control
lines without any possibility of selecting GPIO function.

As a consequence, applications that depends on GPIO lines configured
by default as GPIO pins no longer work as expected.

Also, the change to select modem control lines function was done only
for channel A of dual UART variants (752/762). This was not documented
in the log message.

Allow to specify GPIO or modem control line function in the device
tree, and for each of the ports (A or B).

Do so by using the new device-tree property named
"nxp,modem-control-line-ports" (property added in separate patch).

When registering GPIO chip controller, mask-out GPIO pins declared as
modem control lines according to this new DT property.

Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Reviewed-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Tested-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Acked-by: Rob Herring &lt;robh@kernel.org&gt;
Link: https://lore.kernel.org/r/20230807214556.540627-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: sc16is7xx: remove obsolete out_thread label</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Hugo Villeneuve</name>
<email>hvilleneuve@dimonoff.com</email>
</author>
<published>2023-08-07T21:45:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ccae7cf2d6ffaabbdb4af6c2d5fc2bd88da44a3b'/>
<id>ccae7cf2d6ffaabbdb4af6c2d5fc2bd88da44a3b</id>
<content type='text'>
[ Upstream commit dabc54a45711fe77674a6c0348231e00e66bd567 ]

Commit c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later
in probe") moved GPIO setup code later in probe function. Doing so
also required to move ports cleanup code (out_ports label) after the
GPIO cleanup code.

After these moves, the out_thread label becomes misplaced and makes
part of the cleanup code illogical.

This patch remove the now obsolete out_thread label and make GPIO
setup code jump to out_ports label if it fails.

Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Tested-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Reviewed-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Link: https://lore.kernel.org/r/20230807214556.540627-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Stable-dep-of: 049994292834 ("serial: sc16is7xx: fix regression with GPIO configuration")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit dabc54a45711fe77674a6c0348231e00e66bd567 ]

Commit c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later
in probe") moved GPIO setup code later in probe function. Doing so
also required to move ports cleanup code (out_ports label) after the
GPIO cleanup code.

After these moves, the out_thread label becomes misplaced and makes
part of the cleanup code illogical.

This patch remove the now obsolete out_thread label and make GPIO
setup code jump to out_ports label if it fails.

Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Tested-by: Lech Perczak &lt;lech.perczak@camlingroup.com&gt;
Reviewed-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Link: https://lore.kernel.org/r/20230807214556.540627-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Stable-dep-of: 049994292834 ("serial: sc16is7xx: fix regression with GPIO configuration")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: HCI: Introduce HCI_QUIRK_BROKEN_LE_CODED</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Luiz Augusto von Dentz</name>
<email>luiz.von.dentz@intel.com</email>
</author>
<published>2023-08-22T19:02:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cb3acdc203d689d678abc2800e859b1fb17e3f4f'/>
<id>cb3acdc203d689d678abc2800e859b1fb17e3f4f</id>
<content type='text'>
[ Upstream commit 253f3399f4c09ce6f4e67350f839be0361b4d5ff ]

This introduces HCI_QUIRK_BROKEN_LE_CODED which is used to indicate
that LE Coded PHY shall not be used, it is then set for some Intel
models that claim to support it but when used causes many problems.

Cc: stable@vger.kernel.org # 6.4.y+
Link: https://github.com/bluez/bluez/issues/577
Link: https://github.com/bluez/bluez/issues/582
Link: https://lore.kernel.org/linux-bluetooth/CABBYNZKco-v7wkjHHexxQbgwwSz-S=GZ=dZKbRE1qxT1h4fFbQ@mail.gmail.com/T/#
Fixes: 288c90224eec ("Bluetooth: Enable all supported LE PHY by default")
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 253f3399f4c09ce6f4e67350f839be0361b4d5ff ]

This introduces HCI_QUIRK_BROKEN_LE_CODED which is used to indicate
that LE Coded PHY shall not be used, it is then set for some Intel
models that claim to support it but when used causes many problems.

Cc: stable@vger.kernel.org # 6.4.y+
Link: https://github.com/bluez/bluez/issues/577
Link: https://github.com/bluez/bluez/issues/582
Link: https://lore.kernel.org/linux-bluetooth/CABBYNZKco-v7wkjHHexxQbgwwSz-S=GZ=dZKbRE1qxT1h4fFbQ@mail.gmail.com/T/#
Fixes: 288c90224eec ("Bluetooth: Enable all supported LE PHY by default")
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: msft: Extended monitor tracking by address filter</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Hilda Wu</name>
<email>hildawu@realtek.com</email>
</author>
<published>2023-06-21T10:00:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f9965f7f38c90449a5fb26edb8a7d22b1dcf0283'/>
<id>f9965f7f38c90449a5fb26edb8a7d22b1dcf0283</id>
<content type='text'>
[ Upstream commit 9e14606d8f38ea52a38c27692a9c1513c987a5da ]

Since limited tracking device per condition, this feature is to support
tracking multiple devices concurrently.
When a pattern monitor detects the device, this feature issues an address
monitor for tracking that device. Let pattern monitor can keep monitor
new devices.
This feature adds an address filter when receiving a LE monitor device
event which monitor handle is for a pattern, and the controller started
monitoring the device. And this feature also has cancelled the monitor
advertisement from address filters when receiving a LE monitor device
event when the controller stopped monitoring the device specified by an
address and monitor handle.

Below is an example to know the feature adds the address filter.

//Add MSFT pattern monitor
&lt; HCI Command: Vendor (0x3f|0x00f0) plen 14          #142 [hci0] 55.552420
        03 b8 a4 03 ff 01 01 06 09 05 5f 52 45 46        .........._REF
&gt; HCI Event: Command Complete (0x0e) plen 6          #143 [hci0] 55.653960
      Vendor (0x3f|0x00f0) ncmd 2
        Status: Success (0x00)
        03 00

//Got event from the pattern monitor
&gt; HCI Event: Vendor (0xff) plen 18                   #148 [hci0] 58.384953
        23 79 54 33 77 88 97 68 02 00 fb c1 29 eb 27 b8  #yT3w..h....).'.
        00 01                                            ..

//Add MSFT address monitor (Sample address: B8:27:EB:29:C1:FB)
&lt; HCI Command: Vendor (0x3f|0x00f0) plen 13          #149 [hci0] 58.385067
        03 b8 a4 03 ff 04 00 fb c1 29 eb 27 b8           .........).'.

//Report to userspace about found device (ADV Monitor Device Found)
@ MGMT Event: Unknown (0x002f) plen 38           {0x0003} [hci0] 58.680042
        01 00 fb c1 29 eb 27 b8 01 ce 00 00 00 00 16 00  ....).'.........
        0a 09 4b 45 59 42 44 5f 52 45 46 02 01 06 03 19  ..KEYBD_REF.....
        c1 03 03 03 12 18                                ......

//Got event from address monitor
&gt; HCI Event: Vendor (0xff) plen 18                   #152 [hci0] 58.672956
        23 79 54 33 77 88 97 68 02 00 fb c1 29 eb 27 b8  #yT3w..h....).'.
        01 01

Signed-off-by: Alex Lu &lt;alex_lu@realsil.com.cn&gt;
Signed-off-by: Hilda Wu &lt;hildawu@realtek.com&gt;
Reviewed-by: Simon Horman &lt;simon.horman@corigine.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Stable-dep-of: 253f3399f4c0 ("Bluetooth: HCI: Introduce HCI_QUIRK_BROKEN_LE_CODED")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 9e14606d8f38ea52a38c27692a9c1513c987a5da ]

Since limited tracking device per condition, this feature is to support
tracking multiple devices concurrently.
When a pattern monitor detects the device, this feature issues an address
monitor for tracking that device. Let pattern monitor can keep monitor
new devices.
This feature adds an address filter when receiving a LE monitor device
event which monitor handle is for a pattern, and the controller started
monitoring the device. And this feature also has cancelled the monitor
advertisement from address filters when receiving a LE monitor device
event when the controller stopped monitoring the device specified by an
address and monitor handle.

Below is an example to know the feature adds the address filter.

//Add MSFT pattern monitor
&lt; HCI Command: Vendor (0x3f|0x00f0) plen 14          #142 [hci0] 55.552420
        03 b8 a4 03 ff 01 01 06 09 05 5f 52 45 46        .........._REF
&gt; HCI Event: Command Complete (0x0e) plen 6          #143 [hci0] 55.653960
      Vendor (0x3f|0x00f0) ncmd 2
        Status: Success (0x00)
        03 00

//Got event from the pattern monitor
&gt; HCI Event: Vendor (0xff) plen 18                   #148 [hci0] 58.384953
        23 79 54 33 77 88 97 68 02 00 fb c1 29 eb 27 b8  #yT3w..h....).'.
        00 01                                            ..

//Add MSFT address monitor (Sample address: B8:27:EB:29:C1:FB)
&lt; HCI Command: Vendor (0x3f|0x00f0) plen 13          #149 [hci0] 58.385067
        03 b8 a4 03 ff 04 00 fb c1 29 eb 27 b8           .........).'.

//Report to userspace about found device (ADV Monitor Device Found)
@ MGMT Event: Unknown (0x002f) plen 38           {0x0003} [hci0] 58.680042
        01 00 fb c1 29 eb 27 b8 01 ce 00 00 00 00 16 00  ....).'.........
        0a 09 4b 45 59 42 44 5f 52 45 46 02 01 06 03 19  ..KEYBD_REF.....
        c1 03 03 03 12 18                                ......

//Got event from address monitor
&gt; HCI Event: Vendor (0xff) plen 18                   #152 [hci0] 58.672956
        23 79 54 33 77 88 97 68 02 00 fb c1 29 eb 27 b8  #yT3w..h....).'.
        01 01

Signed-off-by: Alex Lu &lt;alex_lu@realsil.com.cn&gt;
Signed-off-by: Hilda Wu &lt;hildawu@realtek.com&gt;
Reviewed-by: Simon Horman &lt;simon.horman@corigine.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Stable-dep-of: 253f3399f4c0 ("Bluetooth: HCI: Introduce HCI_QUIRK_BROKEN_LE_CODED")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>media: ipu3-cio2: allow ipu_bridge to be a module again</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@kernel.org</email>
</author>
<published>2023-07-27T12:22:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ccdfcb9119674edf3a57d600ddb314a9dfec1389'/>
<id>ccdfcb9119674edf3a57d600ddb314a9dfec1389</id>
<content type='text'>
commit 2545a2c02ba1da9cfb9ec218623c71b00eb4a555 upstream.

This code was previously part of the VIDEO_IPU3_CIO2 driver, which could
be built-in or a loadable module, but after the move it turned into a
builtin-only driver. This fails to link when the I2C subsystem is a
module:

x86_64-linux-ld: drivers/media/pci/intel/ipu-bridge.o: in function `ipu_bridge_unregister_sensors':
ipu-bridge.c:(.text+0x50): undefined reference to `i2c_unregister_device'
x86_64-linux-ld: drivers/media/pci/intel/ipu-bridge.o: in function `ipu_bridge_init':
ipu-bridge.c:(.text+0x9c9): undefined reference to `i2c_acpi_new_device_by_fwnode'

In general, drivers should not have to be built-in, so change the option
to a tristate with the corresponding dependency. This in turn opens a
new problem with the dependency, as the IPU bridge can be a loadable module
while the ipu3 driver itself is built-in, producing a new link failure:

86_64-linux-ld: drivers/media/pci/intel/ipu3/ipu3-cio2.o: in function `cio2_pci_probe':
ipu3-cio2.c:(.text+0x197e): undefined reference to `ipu_bridge_init'

In order to fix this, restore the old Kconfig option that controlled
the ipu bridge driver before it was split out, but make it select a
hidden symbol that now corresponds to the bridge driver.

When other drivers get added that share ipu-bridge, this should cover
all corner cases, and allow any combination of them to be built-in
or modular.

Link: https://lore.kernel.org/linux-media/20230727122331.2421453-1-arnd@kernel.org

Fixes: 881ca25978c6 ("media: ipu3-cio2: rename cio2 bridge to ipu bridge and move out of ipu3")'
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2545a2c02ba1da9cfb9ec218623c71b00eb4a555 upstream.

This code was previously part of the VIDEO_IPU3_CIO2 driver, which could
be built-in or a loadable module, but after the move it turned into a
builtin-only driver. This fails to link when the I2C subsystem is a
module:

x86_64-linux-ld: drivers/media/pci/intel/ipu-bridge.o: in function `ipu_bridge_unregister_sensors':
ipu-bridge.c:(.text+0x50): undefined reference to `i2c_unregister_device'
x86_64-linux-ld: drivers/media/pci/intel/ipu-bridge.o: in function `ipu_bridge_init':
ipu-bridge.c:(.text+0x9c9): undefined reference to `i2c_acpi_new_device_by_fwnode'

In general, drivers should not have to be built-in, so change the option
to a tristate with the corresponding dependency. This in turn opens a
new problem with the dependency, as the IPU bridge can be a loadable module
while the ipu3 driver itself is built-in, producing a new link failure:

86_64-linux-ld: drivers/media/pci/intel/ipu3/ipu3-cio2.o: in function `cio2_pci_probe':
ipu3-cio2.c:(.text+0x197e): undefined reference to `ipu_bridge_init'

In order to fix this, restore the old Kconfig option that controlled
the ipu bridge driver before it was split out, but make it select a
hidden symbol that now corresponds to the bridge driver.

When other drivers get added that share ipu-bridge, this should cover
all corner cases, and allow any combination of them to be built-in
or modular.

Link: https://lore.kernel.org/linux-media/20230727122331.2421453-1-arnd@kernel.org

Fixes: 881ca25978c6 ("media: ipu3-cio2: rename cio2 bridge to ipu bridge and move out of ipu3")'
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Fix oversight in SuperSpeed initialization</title>
<updated>2023-09-13T07:48:44+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2023-08-11T17:38:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8cded8d95372f5d80356e179606ca8da2ddd447f'/>
<id>8cded8d95372f5d80356e179606ca8da2ddd447f</id>
<content type='text'>
commit 59cf445754566984fd55af19ba7146c76e6627bc upstream.

Commit 85d07c556216 ("USB: core: Unite old scheme and new scheme
descriptor reads") altered the way USB devices are enumerated
following detection, and in the process it messed up the
initialization of SuperSpeed (or faster) devices:

[   31.650759] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 2 using xhci_hcd
[   31.663107] usb 2-1: device descriptor read/8, error -71
[   31.952697] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 3 using xhci_hcd
[   31.965122] usb 2-1: device descriptor read/8, error -71
[   32.080991] usb usb2-port1: attempt power cycle
...

The problem was caused by the commit forgetting that in SuperSpeed or
faster devices, the device descriptor uses a logarithmic encoding of
the bMaxPacketSize0 value.  (For some reason I thought the 255 case in
the switch statement was meant for these devices, but it isn't -- it
was meant for Wireless USB and is no longer needed.)

We can fix the oversight by testing for buf-&gt;bMaxPacketSize0 = 9
(meaning 512, the actual maxpacket size for ep0 on all SuperSpeed
devices) and straightening out the logic that checks and adjusts our
initial guesses of the maxpacket value.

Reported-and-tested-by: Thinh Nguyen &lt;Thinh.Nguyen@synopsys.com&gt;
Closes: https://lore.kernel.org/linux-usb/20230810002257.nadxmfmrobkaxgnz@synopsys.com/
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Fixes: 85d07c556216 ("USB: core: Unite old scheme and new scheme descriptor reads")
Link: https://lore.kernel.org/r/8809e6c5-59d5-4d2d-ac8f-6d106658ad73@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 59cf445754566984fd55af19ba7146c76e6627bc upstream.

Commit 85d07c556216 ("USB: core: Unite old scheme and new scheme
descriptor reads") altered the way USB devices are enumerated
following detection, and in the process it messed up the
initialization of SuperSpeed (or faster) devices:

[   31.650759] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 2 using xhci_hcd
[   31.663107] usb 2-1: device descriptor read/8, error -71
[   31.952697] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 3 using xhci_hcd
[   31.965122] usb 2-1: device descriptor read/8, error -71
[   32.080991] usb usb2-port1: attempt power cycle
...

The problem was caused by the commit forgetting that in SuperSpeed or
faster devices, the device descriptor uses a logarithmic encoding of
the bMaxPacketSize0 value.  (For some reason I thought the 255 case in
the switch statement was meant for these devices, but it isn't -- it
was meant for Wireless USB and is no longer needed.)

We can fix the oversight by testing for buf-&gt;bMaxPacketSize0 = 9
(meaning 512, the actual maxpacket size for ep0 on all SuperSpeed
devices) and straightening out the logic that checks and adjusts our
initial guesses of the maxpacket value.

Reported-and-tested-by: Thinh Nguyen &lt;Thinh.Nguyen@synopsys.com&gt;
Closes: https://lore.kernel.org/linux-usb/20230810002257.nadxmfmrobkaxgnz@synopsys.com/
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Fixes: 85d07c556216 ("USB: core: Unite old scheme and new scheme descriptor reads")
Link: https://lore.kernel.org/r/8809e6c5-59d5-4d2d-ac8f-6d106658ad73@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Fix race by not overwriting udev-&gt;descriptor in hub_port_init()</title>
<updated>2023-09-13T07:48:43+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2023-08-04T19:14:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b4a074b1fb222164ed7d5c0b8c922dc4a0840848'/>
<id>b4a074b1fb222164ed7d5c0b8c922dc4a0840848</id>
<content type='text'>
commit ff33299ec8bb80cdcc073ad9c506bd79bb2ed20b upstream.

Syzbot reported an out-of-bounds read in sysfs.c:read_descriptors():

BUG: KASAN: slab-out-of-bounds in read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
Read of size 8 at addr ffff88801e78b8c8 by task udevd/5011

CPU: 0 PID: 5011 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-00195-g40f71e7cd3c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
 print_report mm/kasan/report.c:462 [inline]
 kasan_report+0x11c/0x130 mm/kasan/report.c:572
 read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
...
Allocated by task 758:
...
 __do_kmalloc_node mm/slab_common.c:966 [inline]
 __kmalloc+0x5e/0x190 mm/slab_common.c:979
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:680 [inline]
 usb_get_configuration+0x1f7/0x5170 drivers/usb/core/config.c:887
 usb_enumerate_device drivers/usb/core/hub.c:2407 [inline]
 usb_new_device+0x12b0/0x19d0 drivers/usb/core/hub.c:2545

As analyzed by Khazhy Kumykov, the cause of this bug is a race between
read_descriptors() and hub_port_init(): The first routine uses a field
in udev-&gt;descriptor, not expecting it to change, while the second
overwrites it.

Prior to commit 45bf39f8df7f ("USB: core: Don't hold device lock while
reading the "descriptors" sysfs file") this race couldn't occur,
because the routines were mutually exclusive thanks to the device
locking.  Removing that locking from read_descriptors() exposed it to
the race.

The best way to fix the bug is to keep hub_port_init() from changing
udev-&gt;descriptor once udev has been initialized and registered.
Drivers expect the descriptors stored in the kernel to be immutable;
we should not undermine this expectation.  In fact, this change should
have been made long ago.

So now hub_port_init() will take an additional argument, specifying a
buffer in which to store the device descriptor it reads.  (If udev has
not yet been initialized, the buffer pointer will be NULL and then
hub_port_init() will store the device descriptor in udev as before.)
This eliminates the data race responsible for the out-of-bounds read.

The changes to hub_port_init() appear more extensive than they really
are, because of indentation changes resulting from an attempt to avoid
writing to other parts of the usb_device structure after it has been
initialized.  Similar changes should be made to the code that reads
the BOS descriptor, but that can be handled in a separate patch later
on.  This patch is sufficient to fix the bug found by syzbot.

Reported-and-tested-by: syzbot+18996170f8096c6174d0@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-usb/000000000000c0ffe505fe86c9ca@google.com/#r
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: Khazhy Kumykov &lt;khazhy@google.com&gt;
Fixes: 45bf39f8df7f ("USB: core: Don't hold device lock while reading the "descriptors" sysfs file")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/b958b47a-9a46-4c22-a9f9-e42e42c31251@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ff33299ec8bb80cdcc073ad9c506bd79bb2ed20b upstream.

Syzbot reported an out-of-bounds read in sysfs.c:read_descriptors():

BUG: KASAN: slab-out-of-bounds in read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
Read of size 8 at addr ffff88801e78b8c8 by task udevd/5011

CPU: 0 PID: 5011 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-00195-g40f71e7cd3c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
 print_report mm/kasan/report.c:462 [inline]
 kasan_report+0x11c/0x130 mm/kasan/report.c:572
 read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
...
Allocated by task 758:
...
 __do_kmalloc_node mm/slab_common.c:966 [inline]
 __kmalloc+0x5e/0x190 mm/slab_common.c:979
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:680 [inline]
 usb_get_configuration+0x1f7/0x5170 drivers/usb/core/config.c:887
 usb_enumerate_device drivers/usb/core/hub.c:2407 [inline]
 usb_new_device+0x12b0/0x19d0 drivers/usb/core/hub.c:2545

As analyzed by Khazhy Kumykov, the cause of this bug is a race between
read_descriptors() and hub_port_init(): The first routine uses a field
in udev-&gt;descriptor, not expecting it to change, while the second
overwrites it.

Prior to commit 45bf39f8df7f ("USB: core: Don't hold device lock while
reading the "descriptors" sysfs file") this race couldn't occur,
because the routines were mutually exclusive thanks to the device
locking.  Removing that locking from read_descriptors() exposed it to
the race.

The best way to fix the bug is to keep hub_port_init() from changing
udev-&gt;descriptor once udev has been initialized and registered.
Drivers expect the descriptors stored in the kernel to be immutable;
we should not undermine this expectation.  In fact, this change should
have been made long ago.

So now hub_port_init() will take an additional argument, specifying a
buffer in which to store the device descriptor it reads.  (If udev has
not yet been initialized, the buffer pointer will be NULL and then
hub_port_init() will store the device descriptor in udev as before.)
This eliminates the data race responsible for the out-of-bounds read.

The changes to hub_port_init() appear more extensive than they really
are, because of indentation changes resulting from an attempt to avoid
writing to other parts of the usb_device structure after it has been
initialized.  Similar changes should be made to the code that reads
the BOS descriptor, but that can be handled in a separate patch later
on.  This patch is sufficient to fix the bug found by syzbot.

Reported-and-tested-by: syzbot+18996170f8096c6174d0@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-usb/000000000000c0ffe505fe86c9ca@google.com/#r
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: Khazhy Kumykov &lt;khazhy@google.com&gt;
Fixes: 45bf39f8df7f ("USB: core: Don't hold device lock while reading the "descriptors" sysfs file")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/b958b47a-9a46-4c22-a9f9-e42e42c31251@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Change usb_get_device_descriptor() API</title>
<updated>2023-09-13T07:48:43+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2023-08-04T19:12:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=256b02f63cc13d50bcd4907651c56ffd520806ef'/>
<id>256b02f63cc13d50bcd4907651c56ffd520806ef</id>
<content type='text'>
commit de28e469da75359a2bb8cd8778b78aa64b1be1f4 upstream.

The usb_get_device_descriptor() routine reads the device descriptor
from the udev device and stores it directly in udev-&gt;descriptor.  This
interface is error prone, because the USB subsystem expects in-memory
copies of a device's descriptors to be immutable once the device has
been initialized.

The interface is changed so that the device descriptor is left in a
kmalloc-ed buffer, not copied into the usb_device structure.  A
pointer to the buffer is returned to the caller, who is then
responsible for kfree-ing it.  The corresponding changes needed in the
various callers are fairly small.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit de28e469da75359a2bb8cd8778b78aa64b1be1f4 upstream.

The usb_get_device_descriptor() routine reads the device descriptor
from the udev device and stores it directly in udev-&gt;descriptor.  This
interface is error prone, because the USB subsystem expects in-memory
copies of a device's descriptors to be immutable once the device has
been initialized.

The interface is changed so that the device descriptor is left in a
kmalloc-ed buffer, not copied into the usb_device structure.  A
pointer to the buffer is returned to the caller, who is then
responsible for kfree-ing it.  The corresponding changes needed in the
various callers are fairly small.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Unite old scheme and new scheme descriptor reads</title>
<updated>2023-09-13T07:48:43+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2023-08-04T19:10:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=64687c13eb88667a654f67fa18c1142fb74f27bd'/>
<id>64687c13eb88667a654f67fa18c1142fb74f27bd</id>
<content type='text'>
commit 85d07c55621676d47d873d2749b88f783cd4d5a1 upstream.

In preparation for reworking the usb_get_device_descriptor() routine,
it is desirable to unite the two different code paths responsible for
initially determining endpoint 0's maximum packet size in a newly
discovered USB device.  Making this determination presents a
chicken-and-egg sort of problem, in that the only way to learn the
maxpacket value is to get it from the device descriptor retrieved from
the device, but communicating with the device to retrieve a descriptor
requires us to know beforehand the ep0 maxpacket size.

In practice this problem is solved in two different ways, referred to
in hub.c as the "old scheme" and the "new scheme".  The old scheme
(which is the approach recommended by the USB-2 spec) involves asking
the device to send just the first eight bytes of its device
descriptor.  Such a transfer uses packets containing no more than
eight bytes each, and every USB device must have an ep0 maxpacket size
&gt;= 8, so this should succeed.  Since the bMaxPacketSize0 field of the
device descriptor lies within the first eight bytes, this is all we
need.

The new scheme is an imitation of the technique used in an early
Windows USB implementation, giving it the happy advantage of working
with a wide variety of devices (some of them at the time would not
work with the old scheme, although that's probably less true now).  It
involves making an initial guess of the ep0 maxpacket size, asking the
device to send up to 64 bytes worth of its device descriptor (which is
only 18 bytes long), and then resetting the device to clear any error
condition that might have resulted from the guess being wrong.  The
initial guess is determined by the connection speed; it should be
correct in all cases other than full speed, for which the allowed
values are 8, 16, 32, and 64 (in this case the initial guess is 64).

The reason for this patch is that the old- and new-scheme parts of
hub_port_init() use different code paths, one involving
usb_get_device_descriptor() and one not, for their initial reads of
the device descriptor.  Since these reads have essentially the same
purpose and are made under essentially the same circumstances, this is
illogical.  It makes more sense to have both of them use a common
subroutine.

This subroutine does basically what the new scheme's code did, because
that approach is more general than the one used by the old scheme.  It
only needs to know how many bytes to transfer and whether or not it is
being called for the first iteration of a retry loop (in case of
certain time-out errors).  There are two main differences from the
former code:

	We initialize the bDescriptorType field of the transfer buffer
	to 0 before performing the transfer, to avoid possibly
	accessing an uninitialized value afterward.

	We read the device descriptor into a temporary buffer rather
	than storing it directly into udev-&gt;descriptor, which the old
	scheme implementation used to do.

Since the whole point of this first read of the device descriptor is
to determine the bMaxPacketSize0 value, that is what the new routine
returns (or an error code).  The value is stored in a local variable
rather than in udev-&gt;descriptor.  As a side effect, this necessitates
moving a section of code that checks the bcdUSB field for SuperSpeed
devices until after the full device descriptor has been retrieved.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/495cb5d4-f956-4f4a-a875-1e67e9489510@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 85d07c55621676d47d873d2749b88f783cd4d5a1 upstream.

In preparation for reworking the usb_get_device_descriptor() routine,
it is desirable to unite the two different code paths responsible for
initially determining endpoint 0's maximum packet size in a newly
discovered USB device.  Making this determination presents a
chicken-and-egg sort of problem, in that the only way to learn the
maxpacket value is to get it from the device descriptor retrieved from
the device, but communicating with the device to retrieve a descriptor
requires us to know beforehand the ep0 maxpacket size.

In practice this problem is solved in two different ways, referred to
in hub.c as the "old scheme" and the "new scheme".  The old scheme
(which is the approach recommended by the USB-2 spec) involves asking
the device to send just the first eight bytes of its device
descriptor.  Such a transfer uses packets containing no more than
eight bytes each, and every USB device must have an ep0 maxpacket size
&gt;= 8, so this should succeed.  Since the bMaxPacketSize0 field of the
device descriptor lies within the first eight bytes, this is all we
need.

The new scheme is an imitation of the technique used in an early
Windows USB implementation, giving it the happy advantage of working
with a wide variety of devices (some of them at the time would not
work with the old scheme, although that's probably less true now).  It
involves making an initial guess of the ep0 maxpacket size, asking the
device to send up to 64 bytes worth of its device descriptor (which is
only 18 bytes long), and then resetting the device to clear any error
condition that might have resulted from the guess being wrong.  The
initial guess is determined by the connection speed; it should be
correct in all cases other than full speed, for which the allowed
values are 8, 16, 32, and 64 (in this case the initial guess is 64).

The reason for this patch is that the old- and new-scheme parts of
hub_port_init() use different code paths, one involving
usb_get_device_descriptor() and one not, for their initial reads of
the device descriptor.  Since these reads have essentially the same
purpose and are made under essentially the same circumstances, this is
illogical.  It makes more sense to have both of them use a common
subroutine.

This subroutine does basically what the new scheme's code did, because
that approach is more general than the one used by the old scheme.  It
only needs to know how many bytes to transfer and whether or not it is
being called for the first iteration of a retry loop (in case of
certain time-out errors).  There are two main differences from the
former code:

	We initialize the bDescriptorType field of the transfer buffer
	to 0 before performing the transfer, to avoid possibly
	accessing an uninitialized value afterward.

	We read the device descriptor into a temporary buffer rather
	than storing it directly into udev-&gt;descriptor, which the old
	scheme implementation used to do.

Since the whole point of this first read of the device descriptor is
to determine the bMaxPacketSize0 value, that is what the new routine
returns (or an error code).  The value is stored in a local variable
rather than in udev-&gt;descriptor.  As a side effect, this necessitates
moving a section of code that checks the bcdUSB field for SuperSpeed
devices until after the full device descriptor has been retrieved.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/495cb5d4-f956-4f4a-a875-1e67e9489510@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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