<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/gpu, branch v4.19.49</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drm/lease: Make sure implicit planes are leased</title>
<updated>2019-06-09T07:17:23+00:00</updated>
<author>
<name>Daniel Vetter</name>
<email>daniel.vetter@ffwll.ch</email>
</author>
<published>2019-02-28T14:49:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=390a0fd31b02f2f7086af2f3bdb8ae576b9a4b84'/>
<id>390a0fd31b02f2f7086af2f3bdb8ae576b9a4b84</id>
<content type='text'>
commit 204f640da6914844b3270b41b29c84f6e3b74083 upstream.

If userspace doesn't enable universal planes, then we automatically
add the primary and cursor planes. But for universal userspace there's
no such check (and maybe we only want to give the lessee one plane,
maybe not even the primary one), hence we need to check for the
implied plane.

v2: don't forget setcrtc ioctl.

v3: Still allow disabling of the crtc in SETCRTC.

Cc: stable@vger.kernel.org
Cc: Keith Packard &lt;keithp@keithp.com&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@collabora.com&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190228144910.26488-6-daniel.vetter@ffwll.ch
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 204f640da6914844b3270b41b29c84f6e3b74083 upstream.

If userspace doesn't enable universal planes, then we automatically
add the primary and cursor planes. But for universal userspace there's
no such check (and maybe we only want to give the lessee one plane,
maybe not even the primary one), hence we need to check for the
implied plane.

v2: don't forget setcrtc ioctl.

v3: Still allow disabling of the crtc in SETCRTC.

Cc: stable@vger.kernel.org
Cc: Keith Packard &lt;keithp@keithp.com&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@collabora.com&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190228144910.26488-6-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/rockchip: shutdown drm subsystem on shutdown</title>
<updated>2019-06-09T07:17:23+00:00</updated>
<author>
<name>Vicente Bergas</name>
<email>vicencb@gmail.com</email>
</author>
<published>2019-04-02T11:37:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=699f0e9d24c85545403794208051c5a5f5633dad'/>
<id>699f0e9d24c85545403794208051c5a5f5633dad</id>
<content type='text'>
commit b8f9d7f37b6af829c34c49d1a4f73ce6ed58e403 upstream.

As explained by Robin Murphy:
&gt; the IOMMU shutdown disables paging, so if the VOP is still
&gt; scanning out then that will result in whatever IOVAs it was using now going
&gt; straight out onto the bus as physical addresses.

We had a more radical approach before in commit
7f3ef5dedb14 ("drm/rockchip: Allow driver to be shutdown on reboot/kexec")
but that resulted in new warnings and oopses on shutdown on rk3399
chromeos devices.

So second try is resurrecting Vicentes shutdown change which should
achieve the same result but in a less drastic way.

Fixes: 63238173b2fa ("Revert "drm/rockchip: Allow driver to be shutdown on reboot/kexec"")
Cc: Jeffy Chen &lt;jeffy.chen@rock-chips.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Brian Norris &lt;briannorris@chromium.org&gt;
Cc: Doug Anderson &lt;dianders@chromium.org&gt;
Cc: stable@vger.kernel.org
Suggested-by: JeffyChen &lt;jeffy.chen@rock-chips.com&gt;
Suggested-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Signed-off-by: Vicente Bergas &lt;vicencb@gmail.com&gt;
[adapted commit message to explain the history]
Signed-off-by: Heiko Stuebner &lt;heiko@sntech.de&gt;
Tested-by: Brian Norris &lt;briannorris@chromium.org&gt;
Tested-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Acked-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190402113753.10118-1-heiko@sntech.de
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 b8f9d7f37b6af829c34c49d1a4f73ce6ed58e403 upstream.

As explained by Robin Murphy:
&gt; the IOMMU shutdown disables paging, so if the VOP is still
&gt; scanning out then that will result in whatever IOVAs it was using now going
&gt; straight out onto the bus as physical addresses.

We had a more radical approach before in commit
7f3ef5dedb14 ("drm/rockchip: Allow driver to be shutdown on reboot/kexec")
but that resulted in new warnings and oopses on shutdown on rk3399
chromeos devices.

So second try is resurrecting Vicentes shutdown change which should
achieve the same result but in a less drastic way.

Fixes: 63238173b2fa ("Revert "drm/rockchip: Allow driver to be shutdown on reboot/kexec"")
Cc: Jeffy Chen &lt;jeffy.chen@rock-chips.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Brian Norris &lt;briannorris@chromium.org&gt;
Cc: Doug Anderson &lt;dianders@chromium.org&gt;
Cc: stable@vger.kernel.org
Suggested-by: JeffyChen &lt;jeffy.chen@rock-chips.com&gt;
Suggested-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Signed-off-by: Vicente Bergas &lt;vicencb@gmail.com&gt;
[adapted commit message to explain the history]
Signed-off-by: Heiko Stuebner &lt;heiko@sntech.de&gt;
Tested-by: Brian Norris &lt;briannorris@chromium.org&gt;
Tested-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Acked-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190402113753.10118-1-heiko@sntech.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: Fix sun8i HDMI PHY configuration for &gt; 148.5 MHz</title>
<updated>2019-06-09T07:17:23+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2019-05-14T20:43:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1ca811507e416b774681447df27be134485fd155'/>
<id>1ca811507e416b774681447df27be134485fd155</id>
<content type='text'>
commit 831adffb3b7b8df4c8e20b7b00843129fb87a166 upstream.

Vendor provided documentation says that EMP bits should be set to 3 for
pixel clocks greater than 148.5 MHz.

Fix that.

Cc: stable@vger.kernel.org # 4.17+
Fixes: 4f86e81748fe ("drm/sun4i: Add support for H3 HDMI PHY variant")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190514204337.11068-3-jernej.skrabec@siol.net
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 831adffb3b7b8df4c8e20b7b00843129fb87a166 upstream.

Vendor provided documentation says that EMP bits should be set to 3 for
pixel clocks greater than 148.5 MHz.

Fix that.

Cc: stable@vger.kernel.org # 4.17+
Fixes: 4f86e81748fe ("drm/sun4i: Add support for H3 HDMI PHY variant")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190514204337.11068-3-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: Fix sun8i HDMI PHY clock initialization</title>
<updated>2019-06-09T07:17:22+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2019-05-14T20:43:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1f1372206e0b2bf9e5208df3e603c84fa85b0d94'/>
<id>1f1372206e0b2bf9e5208df3e603c84fa85b0d94</id>
<content type='text'>
commit 8a943c6021ba8b95a36c842327e468df1fddd4a7 upstream.

Current code initializes HDMI PHY clock driver before reset line is
deasserted and clocks enabled. Because of that, initial readout of
clock divider is incorrect (0 instead of 2). This causes any clock
rate with divider 1 (register value 0) to be set incorrectly.

Fix this by moving initialization of HDMI PHY clock driver after reset
line is deasserted and clocks enabled.

Cc: stable@vger.kernel.org # 4.17+
Fixes: 4f86e81748fe ("drm/sun4i: Add support for H3 HDMI PHY variant")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190514204337.11068-2-jernej.skrabec@siol.net
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 8a943c6021ba8b95a36c842327e468df1fddd4a7 upstream.

Current code initializes HDMI PHY clock driver before reset line is
deasserted and clocks enabled. Because of that, initial readout of
clock divider is incorrect (0 instead of 2). This causes any clock
rate with divider 1 (register value 0) to be set incorrectly.

Fix this by moving initialization of HDMI PHY clock driver after reset
line is deasserted and clocks enabled.

Cc: stable@vger.kernel.org # 4.17+
Fixes: 4f86e81748fe ("drm/sun4i: Add support for H3 HDMI PHY variant")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190514204337.11068-2-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/vmwgfx: Don't send drm sysfs hotplug events on initial master set</title>
<updated>2019-06-09T07:17:22+00:00</updated>
<author>
<name>Thomas Hellstrom</name>
<email>thellstrom@vmware.com</email>
</author>
<published>2019-05-07T09:07:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3a20515c3c44b13d4851f408cc4d5e1ac32688f1'/>
<id>3a20515c3c44b13d4851f408cc4d5e1ac32688f1</id>
<content type='text'>
commit 63cb44441826e842b7285575b96db631cc9f2505 upstream.

This may confuse user-space clients like plymouth that opens a drm
file descriptor as a result of a hotplug event and then generates a
new event...

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: 5ea1734827bb ("drm/vmwgfx: Send a hotplug event at master_set")
Signed-off-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Reviewed-by: Deepak Rawat &lt;drawat@vmware.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 63cb44441826e842b7285575b96db631cc9f2505 upstream.

This may confuse user-space clients like plymouth that opens a drm
file descriptor as a result of a hotplug event and then generates a
new event...

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: 5ea1734827bb ("drm/vmwgfx: Send a hotplug event at master_set")
Signed-off-by: Thomas Hellstrom &lt;thellstrom@vmware.com&gt;
Reviewed-by: Deepak Rawat &lt;drawat@vmware.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/tegra: gem: Fix CPU-cache maintenance for BO's allocated using get_pages()</title>
<updated>2019-06-09T07:17:22+00:00</updated>
<author>
<name>Dmitry Osipenko</name>
<email>digetx@gmail.com</email>
</author>
<published>2019-03-06T22:55:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1715a46322fa17037f2b1cc05f3cf9e1046c8a9e'/>
<id>1715a46322fa17037f2b1cc05f3cf9e1046c8a9e</id>
<content type='text'>
commit 61b51fb51c01a519a249d28ec55c6513a13be5a3 upstream.

The allocated pages need to be invalidated in CPU caches. On ARM32 the
DMA_BIDIRECTIONAL flag only ensures that data is written-back to DRAM and
the data stays in CPU cache lines. While the DMA_FROM_DEVICE flag ensures
that the corresponding CPU cache lines are getting invalidated and nothing
more, that's exactly what is needed for a newly allocated pages.

This fixes randomly failing rendercheck tests on Tegra30 using the
Opentegra driver for tests that use small-sized pixmaps (10x10 and less,
i.e. 1-2 memory pages) because apparently CPU reads out stale data from
caches and/or that data is getting evicted to DRAM at the time of HW job
execution.

Fixes: bd43c9f0fa1f ("drm/tegra: gem: Map pages via the DMA API")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Dmitry Osipenko &lt;digetx@gmail.com&gt;
Signed-off-by: Thierry Reding &lt;treding@nvidia.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 61b51fb51c01a519a249d28ec55c6513a13be5a3 upstream.

The allocated pages need to be invalidated in CPU caches. On ARM32 the
DMA_BIDIRECTIONAL flag only ensures that data is written-back to DRAM and
the data stays in CPU cache lines. While the DMA_FROM_DEVICE flag ensures
that the corresponding CPU cache lines are getting invalidated and nothing
more, that's exactly what is needed for a newly allocated pages.

This fixes randomly failing rendercheck tests on Tegra30 using the
Opentegra driver for tests that use small-sized pixmaps (10x10 and less,
i.e. 1-2 memory pages) because apparently CPU reads out stale data from
caches and/or that data is getting evicted to DRAM at the time of HW job
execution.

Fixes: bd43c9f0fa1f ("drm/tegra: gem: Map pages via the DMA API")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Dmitry Osipenko &lt;digetx@gmail.com&gt;
Signed-off-by: Thierry Reding &lt;treding@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/nouveau/i2c: Disable i2c bus access after -&gt;fini()</title>
<updated>2019-06-09T07:17:18+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2019-04-09T20:23:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=88ad86b807823791ab4f87b25f2100dc6189d3ba'/>
<id>88ad86b807823791ab4f87b25f2100dc6189d3ba</id>
<content type='text'>
commit 342406e4fbba9a174125fbfe6aeac3d64ef90f76 upstream.

For a while, we've had the problem of i2c bus access not grabbing
a runtime PM ref when it's being used in userspace by i2c-dev, resulting
in nouveau spamming the kernel log with errors if anything attempts to
access the i2c bus while the GPU is in runtime suspend. An example:

[  130.078386] nouveau 0000:01:00.0: i2c: aux 000d: begin idle timeout ffffffff

Since the GPU is in runtime suspend, the MMIO region that the i2c bus is
on isn't accessible. On x86, the standard behavior for accessing an
unavailable MMIO region is to just return ~0.

Except, that turned out to be a lie. While computers with a clean
concious will return ~0 in this scenario, some machines will actually
completely hang a CPU on certian bad MMIO accesses. This was witnessed
with someone's Lenovo ThinkPad P50, where sensors-detect attempting to
access the i2c bus while the GPU was suspended would result in a CPU
hang:

  CPU: 5 PID: 12438 Comm: sensors-detect Not tainted 5.0.0-0.rc4.git3.1.fc30.x86_64 #1
  Hardware name: LENOVO 20EQS64N17/20EQS64N17, BIOS N1EET74W (1.47 ) 11/21/2017
  RIP: 0010:ioread32+0x2b/0x30
  Code: 81 ff ff ff 03 00 77 20 48 81 ff 00 00 01 00 76 05 0f b7 d7 ed c3
  48 c7 c6 e1 0c 36 96 e8 2d ff ff ff b8 ff ff ff ff c3 8b 07 &lt;c3&gt; 0f 1f
  40 00 49 89 f0 48 81 fe ff ff 03 00 76 04 40 88 3e c3 48
  RSP: 0018:ffffaac3c5007b48 EFLAGS: 00000292 ORIG_RAX: ffffffffffffff13
  RAX: 0000000001111000 RBX: 0000000001111000 RCX: 0000043017a97186
  RDX: 0000000000000aaa RSI: 0000000000000005 RDI: ffffaac3c400e4e4
  RBP: ffff9e6443902c00 R08: ffffaac3c400e4e4 R09: ffffaac3c5007be7
  R10: 0000000000000004 R11: 0000000000000001 R12: ffff9e6445dd0000
  R13: 000000000000e4e4 R14: 00000000000003c4 R15: 0000000000000000
  FS:  00007f253155a740(0000) GS:ffff9e644f600000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00005630d1500358 CR3: 0000000417c44006 CR4: 00000000003606e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   g94_i2c_aux_xfer+0x326/0x850 [nouveau]
   nvkm_i2c_aux_i2c_xfer+0x9e/0x140 [nouveau]
   __i2c_transfer+0x14b/0x620
   i2c_smbus_xfer_emulated+0x159/0x680
   ? _raw_spin_unlock_irqrestore+0x1/0x60
   ? rt_mutex_slowlock.constprop.0+0x13d/0x1e0
   ? __lock_is_held+0x59/0xa0
   __i2c_smbus_xfer+0x138/0x5a0
   i2c_smbus_xfer+0x4f/0x80
   i2cdev_ioctl_smbus+0x162/0x2d0 [i2c_dev]
   i2cdev_ioctl+0x1db/0x2c0 [i2c_dev]
   do_vfs_ioctl+0x408/0x750
   ksys_ioctl+0x5e/0x90
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x60/0x1e0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7f25317f546b
  Code: 0f 1e fa 48 8b 05 1d da 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
  ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 &lt;48&gt; 3d 01
  f0 ff ff 73 01 c3 48 8b 0d ed d9 0c 00 f7 d8 64 89 01 48
  RSP: 002b:00007ffc88caab68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00005630d0fe7260 RCX: 00007f25317f546b
  RDX: 00005630d1598e80 RSI: 0000000000000720 RDI: 0000000000000003
  RBP: 00005630d155b968 R08: 0000000000000001 R09: 00005630d15a1da0
  R10: 0000000000000070 R11: 0000000000000246 R12: 00005630d1598e80
  R13: 00005630d12f3d28 R14: 0000000000000720 R15: 00005630d12f3ce0
  watchdog: BUG: soft lockup - CPU#5 stuck for 23s! [sensors-detect:12438]

Yikes! While I wanted to try to make it so that accessing an i2c bus on
nouveau would wake up the GPU as needed, airlied pointed out that pretty
much any usecase for userspace accessing an i2c bus on a GPU (mainly for
the DDC brightness control that some displays have) is going to only be
useful while there's at least one display enabled on the GPU anyway, and
the GPU never sleeps while there's displays running.

Since teaching the i2c bus to wake up the GPU on userspace accesses is a
good deal more difficult than it might seem, mostly due to the fact that
we have to use the i2c bus during runtime resume of the GPU, we instead
opt for the easiest solution: don't let userspace access i2c busses on
the GPU at all while it's in runtime suspend.

Changes since v1:
* Also disable i2c busses that run over DP AUX

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.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 342406e4fbba9a174125fbfe6aeac3d64ef90f76 upstream.

For a while, we've had the problem of i2c bus access not grabbing
a runtime PM ref when it's being used in userspace by i2c-dev, resulting
in nouveau spamming the kernel log with errors if anything attempts to
access the i2c bus while the GPU is in runtime suspend. An example:

[  130.078386] nouveau 0000:01:00.0: i2c: aux 000d: begin idle timeout ffffffff

Since the GPU is in runtime suspend, the MMIO region that the i2c bus is
on isn't accessible. On x86, the standard behavior for accessing an
unavailable MMIO region is to just return ~0.

Except, that turned out to be a lie. While computers with a clean
concious will return ~0 in this scenario, some machines will actually
completely hang a CPU on certian bad MMIO accesses. This was witnessed
with someone's Lenovo ThinkPad P50, where sensors-detect attempting to
access the i2c bus while the GPU was suspended would result in a CPU
hang:

  CPU: 5 PID: 12438 Comm: sensors-detect Not tainted 5.0.0-0.rc4.git3.1.fc30.x86_64 #1
  Hardware name: LENOVO 20EQS64N17/20EQS64N17, BIOS N1EET74W (1.47 ) 11/21/2017
  RIP: 0010:ioread32+0x2b/0x30
  Code: 81 ff ff ff 03 00 77 20 48 81 ff 00 00 01 00 76 05 0f b7 d7 ed c3
  48 c7 c6 e1 0c 36 96 e8 2d ff ff ff b8 ff ff ff ff c3 8b 07 &lt;c3&gt; 0f 1f
  40 00 49 89 f0 48 81 fe ff ff 03 00 76 04 40 88 3e c3 48
  RSP: 0018:ffffaac3c5007b48 EFLAGS: 00000292 ORIG_RAX: ffffffffffffff13
  RAX: 0000000001111000 RBX: 0000000001111000 RCX: 0000043017a97186
  RDX: 0000000000000aaa RSI: 0000000000000005 RDI: ffffaac3c400e4e4
  RBP: ffff9e6443902c00 R08: ffffaac3c400e4e4 R09: ffffaac3c5007be7
  R10: 0000000000000004 R11: 0000000000000001 R12: ffff9e6445dd0000
  R13: 000000000000e4e4 R14: 00000000000003c4 R15: 0000000000000000
  FS:  00007f253155a740(0000) GS:ffff9e644f600000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00005630d1500358 CR3: 0000000417c44006 CR4: 00000000003606e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   g94_i2c_aux_xfer+0x326/0x850 [nouveau]
   nvkm_i2c_aux_i2c_xfer+0x9e/0x140 [nouveau]
   __i2c_transfer+0x14b/0x620
   i2c_smbus_xfer_emulated+0x159/0x680
   ? _raw_spin_unlock_irqrestore+0x1/0x60
   ? rt_mutex_slowlock.constprop.0+0x13d/0x1e0
   ? __lock_is_held+0x59/0xa0
   __i2c_smbus_xfer+0x138/0x5a0
   i2c_smbus_xfer+0x4f/0x80
   i2cdev_ioctl_smbus+0x162/0x2d0 [i2c_dev]
   i2cdev_ioctl+0x1db/0x2c0 [i2c_dev]
   do_vfs_ioctl+0x408/0x750
   ksys_ioctl+0x5e/0x90
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x60/0x1e0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7f25317f546b
  Code: 0f 1e fa 48 8b 05 1d da 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
  ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 &lt;48&gt; 3d 01
  f0 ff ff 73 01 c3 48 8b 0d ed d9 0c 00 f7 d8 64 89 01 48
  RSP: 002b:00007ffc88caab68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00005630d0fe7260 RCX: 00007f25317f546b
  RDX: 00005630d1598e80 RSI: 0000000000000720 RDI: 0000000000000003
  RBP: 00005630d155b968 R08: 0000000000000001 R09: 00005630d15a1da0
  R10: 0000000000000070 R11: 0000000000000246 R12: 00005630d1598e80
  R13: 00005630d12f3d28 R14: 0000000000000720 R15: 00005630d12f3ce0
  watchdog: BUG: soft lockup - CPU#5 stuck for 23s! [sensors-detect:12438]

Yikes! While I wanted to try to make it so that accessing an i2c bus on
nouveau would wake up the GPU as needed, airlied pointed out that pretty
much any usecase for userspace accessing an i2c bus on a GPU (mainly for
the DDC brightness control that some displays have) is going to only be
useful while there's at least one display enabled on the GPU anyway, and
the GPU never sleeps while there's displays running.

Since teaching the i2c bus to wake up the GPU on userspace accesses is a
good deal more difficult than it might seem, mostly due to the fact that
we have to use the i2c bus during runtime resume of the GPU, we instead
opt for the easiest solution: don't let userspace access i2c busses on
the GPU at all while it's in runtime suspend.

Changes since v1:
* Also disable i2c busses that run over DP AUX

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: dsi: Enforce boundaries on the start delay</title>
<updated>2019-05-31T13:46:35+00:00</updated>
<author>
<name>Maxime Ripard</name>
<email>maxime.ripard@bootlin.com</email>
</author>
<published>2019-02-11T14:41:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1a686177acdec679c90200c0f5db04155a1c4493'/>
<id>1a686177acdec679c90200c0f5db04155a1c4493</id>
<content type='text'>
[ Upstream commit efa31801203ac2f5c6a82a28cb991c7163ee0f1d ]

The Allwinner BSP makes sure that we don't end up with a null start delay
or with a delay larger than vtotal.

The former condition is likely to happen now with the reworked start delay,
so make sure we enforce the same boundaries.

Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/c9889cf5f7a3d101ef380905900b45a182596f56.1549896081.git-series.maxime.ripard@bootlin.com
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 efa31801203ac2f5c6a82a28cb991c7163ee0f1d ]

The Allwinner BSP makes sure that we don't end up with a null start delay
or with a delay larger than vtotal.

The former condition is likely to happen now with the reworked start delay,
so make sure we enforce the same boundaries.

Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/c9889cf5f7a3d101ef380905900b45a182596f56.1549896081.git-series.maxime.ripard@bootlin.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: dsi: Change the start delay calculation</title>
<updated>2019-05-31T13:46:34+00:00</updated>
<author>
<name>Maxime Ripard</name>
<email>maxime.ripard@bootlin.com</email>
</author>
<published>2019-02-11T14:41:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=476e87eb7f78b344c2312c74cc289b1843deadd8'/>
<id>476e87eb7f78b344c2312c74cc289b1843deadd8</id>
<content type='text'>
[ Upstream commit da676c6aa6413d59ab0a80c97bbc273025e640b2 ]

The current calculation for the video start delay in the current DSI driver
is that it is the total vertical size, minus the front porch and sync length,
plus 1. This equals to the active vertical size plus the back porch plus 1.

That 1 is coming in the Allwinner BSP from an variable that is set to 1.
However, if we look at the Allwinner BSP more closely, and especially in
the "legacy" code for the display (in drivers/video/sunxi/legacy/), we can
see that this variable is actually computed from the porches and the sync
minus 10, clamped between 8 and 100.

This fixes the start delay symptom we've seen on some panels (vblank
timeouts with vertical white stripes at the bottom of the panel).

Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/6e5f72e68f47ca0223877464bf12f0c3f3978de8.1549896081.git-series.maxime.ripard@bootlin.com
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 da676c6aa6413d59ab0a80c97bbc273025e640b2 ]

The current calculation for the video start delay in the current DSI driver
is that it is the total vertical size, minus the front porch and sync length,
plus 1. This equals to the active vertical size plus the back porch plus 1.

That 1 is coming in the Allwinner BSP from an variable that is set to 1.
However, if we look at the Allwinner BSP more closely, and especially in
the "legacy" code for the display (in drivers/video/sunxi/legacy/), we can
see that this variable is actually computed from the porches and the sync
minus 10, clamped between 8 and 100.

This fixes the start delay symptom we've seen on some panels (vblank
timeouts with vertical white stripes at the bottom of the panel).

Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/6e5f72e68f47ca0223877464bf12f0c3f3978de8.1549896081.git-series.maxime.ripard@bootlin.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: Wake up next in drm_read() chain if we are forced to putback the event</title>
<updated>2019-05-31T13:46:34+00:00</updated>
<author>
<name>Chris Wilson</name>
<email>chris@chris-wilson.co.uk</email>
</author>
<published>2017-08-04T08:23:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=00734a9e7329acc48e575f697ee4118998c1dac0'/>
<id>00734a9e7329acc48e575f697ee4118998c1dac0</id>
<content type='text'>
[ Upstream commit 60b801999c48b6c1dd04e653a38e2e613664264e ]

After an event is sent, we try to copy it into the user buffer of the
first waiter in drm_read() and if the user buffer doesn't have enough
room we put it back onto the list. However, we didn't wake up any
subsequent waiter, so that event may sit on the list until either a new
vblank event is sent or a new waiter appears. Rare, but in the worst
case may lead to a stuck process.

Testcase: igt/drm_read/short-buffer-wakeup
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20170804082328.17173-1-chris@chris-wilson.co.uk
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 60b801999c48b6c1dd04e653a38e2e613664264e ]

After an event is sent, we try to copy it into the user buffer of the
first waiter in drm_read() and if the user buffer doesn't have enough
room we put it back onto the list. However, we didn't wake up any
subsequent waiter, so that event may sit on the list until either a new
vblank event is sent or a new waiter appears. Rare, but in the worst
case may lead to a stuck process.

Testcase: igt/drm_read/short-buffer-wakeup
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20170804082328.17173-1-chris@chris-wilson.co.uk
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
