<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/gpu/drm, branch v5.6.6</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drm/i915/perf: Do not clear pollin for small user read buffers</title>
<updated>2020-04-21T07:08:13+00:00</updated>
<author>
<name>Ashutosh Dixit</name>
<email>ashutosh.dixit@intel.com</email>
</author>
<published>2020-04-08T23:42:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=634781fc6f75bd185907607bd22d275ed49d82f8'/>
<id>634781fc6f75bd185907607bd22d275ed49d82f8</id>
<content type='text'>
commit bcad588dea538a4fc173d16a90a005536ec8dbf2 upstream.

It is wrong to block the user thread in the next poll when OA data is
already available which could not fit in the user buffer provided in
the previous read. In several cases the exact user buffer size is not
known. Blocking user space in poll can lead to data loss when the
buffer size used is smaller than the available data.

This change fixes this issue and allows user space to read all OA data
even when using a buffer size smaller than the available data using
multiple non-blocking reads rather than staying blocked in poll till
the next timer interrupt.

v2: Fix ret value for blocking reads (Umesh)
v3: Mistake during patch send (Ashutosh)
v4: Remove -EAGAIN from comment (Umesh)
v5: Improve condition for clearing pollin and return (Lionel)
v6: Improve blocking read loop and other cleanups (Lionel)
v7: Added Cc stable

Testcase: igt/perf/polling-small-buf
Reviewed-by: Lionel Landwerlin &lt;lionel.g.landwerlin@intel.com&gt;
Signed-off-by: Ashutosh Dixit &lt;ashutosh.dixit@intel.com&gt;
Cc: Umesh Nerlige Ramappa &lt;umesh.nerlige.ramappa@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200403010120.3067-1-ashutosh.dixit@intel.com
(cherry-picked from commit 6352219c39c04ed3f9a8d1cf93f87c21753a213e)
Signed-off-by: Rodrigo Vivi &lt;rodrigo.vivi@intel.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 bcad588dea538a4fc173d16a90a005536ec8dbf2 upstream.

It is wrong to block the user thread in the next poll when OA data is
already available which could not fit in the user buffer provided in
the previous read. In several cases the exact user buffer size is not
known. Blocking user space in poll can lead to data loss when the
buffer size used is smaller than the available data.

This change fixes this issue and allows user space to read all OA data
even when using a buffer size smaller than the available data using
multiple non-blocking reads rather than staying blocked in poll till
the next timer interrupt.

v2: Fix ret value for blocking reads (Umesh)
v3: Mistake during patch send (Ashutosh)
v4: Remove -EAGAIN from comment (Umesh)
v5: Improve condition for clearing pollin and return (Lionel)
v6: Improve blocking read loop and other cleanups (Lionel)
v7: Added Cc stable

Testcase: igt/perf/polling-small-buf
Reviewed-by: Lionel Landwerlin &lt;lionel.g.landwerlin@intel.com&gt;
Signed-off-by: Ashutosh Dixit &lt;ashutosh.dixit@intel.com&gt;
Cc: Umesh Nerlige Ramappa &lt;umesh.nerlige.ramappa@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200403010120.3067-1-ashutosh.dixit@intel.com
(cherry-picked from commit 6352219c39c04ed3f9a8d1cf93f87c21753a213e)
Signed-off-by: Rodrigo Vivi &lt;rodrigo.vivi@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/nouveau/sec2/gv100-: add missing MODULE_FIRMWARE()</title>
<updated>2020-04-21T07:08:13+00:00</updated>
<author>
<name>Ben Skeggs</name>
<email>bskeggs@redhat.com</email>
</author>
<published>2020-04-16T05:26:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5e69e5904b9c19a48c3b3bf24a8395f0144027bc'/>
<id>5e69e5904b9c19a48c3b3bf24a8395f0144027bc</id>
<content type='text'>
commit 92f673a12d14b5393138d2b1cfeb41d72b47362d upstream.

ASB was failing to load on Turing GPUs when firmware is being loaded
from initramfs, leaving the GPU in an odd state and causing suspend/
resume to fail.

Add missing MODULE_FIRMWARE() lines for initramfs generators.

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6
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 92f673a12d14b5393138d2b1cfeb41d72b47362d upstream.

ASB was failing to load on Turing GPUs when firmware is being loaded
from initramfs, leaving the GPU in an odd state and causing suspend/
resume to fail.

Add missing MODULE_FIRMWARE() lines for initramfs generators.

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu: fix the hw hang during perform system reboot and reset</title>
<updated>2020-04-21T07:08:12+00:00</updated>
<author>
<name>Prike Liang</name>
<email>Prike.Liang@amd.com</email>
</author>
<published>2020-04-13T13:41:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=76b17a574d89e0da56725729c437dee9aef153a0'/>
<id>76b17a574d89e0da56725729c437dee9aef153a0</id>
<content type='text'>
commit b2a7e9735ab2864330be9d00d7f38c961c28de5d upstream.

The system reboot failed as some IP blocks enter power gate before perform
hw resource destory. Meanwhile use unify interface to set device CGPG to ungate
state can simplify the amdgpu poweroff or reset ungate guard.

Fixes: 487eca11a321ef ("drm/amdgpu: fix gfx hang during suspend with video playback (v2)")
Signed-off-by: Prike Liang &lt;Prike.Liang@amd.com&gt;
Tested-by: Mengbing Wang &lt;Mengbing.Wang@amd.com&gt;
Tested-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
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 b2a7e9735ab2864330be9d00d7f38c961c28de5d upstream.

The system reboot failed as some IP blocks enter power gate before perform
hw resource destory. Meanwhile use unify interface to set device CGPG to ungate
state can simplify the amdgpu poweroff or reset ungate guard.

Fixes: 487eca11a321ef ("drm/amdgpu: fix gfx hang during suspend with video playback (v2)")
Signed-off-by: Prike Liang &lt;Prike.Liang@amd.com&gt;
Tested-by: Mengbing Wang &lt;Mengbing.Wang@amd.com&gt;
Tested-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/gfx9: add gfxoff quirk</title>
<updated>2020-04-21T07:08:12+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2020-04-09T13:40:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0321ce45e382f7bfaaf26d8a753049411a890788'/>
<id>0321ce45e382f7bfaaf26d8a753049411a890788</id>
<content type='text'>
commit 974229db7e6c1f2ff83ceaf3022d5128bf62caca upstream.

Fix screen corruption with firefox.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=207171
Reviewed-by: Huang Rui &lt;ray.huang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
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 974229db7e6c1f2ff83ceaf3022d5128bf62caca upstream.

Fix screen corruption with firefox.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=207171
Reviewed-by: Huang Rui &lt;ray.huang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/powerplay: force the trim of the mclk dpm_levels if OD is enabled</title>
<updated>2020-04-21T07:08:12+00:00</updated>
<author>
<name>Sergei Lopatin</name>
<email>magist3r@gmail.com</email>
</author>
<published>2019-06-26T09:56:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eee7960b8c06b2df8faf116ceedfb0b7e771285b'/>
<id>eee7960b8c06b2df8faf116ceedfb0b7e771285b</id>
<content type='text'>
commit 8c7f0a44b4b4ef16df8f44fbaee6d1f5d1593c83 upstream.

Should prevent flicker if PP_OVERDRIVE_MASK is set.

bug: https://bugs.freedesktop.org/show_bug.cgi?id=102646
bug: https://bugs.freedesktop.org/show_bug.cgi?id=108941
bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1088
bug: https://gitlab.freedesktop.org/drm/amd/-/issues/628

Signed-off-by: Sergei Lopatin &lt;magist3r@gmail.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
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 8c7f0a44b4b4ef16df8f44fbaee6d1f5d1593c83 upstream.

Should prevent flicker if PP_OVERDRIVE_MASK is set.

bug: https://bugs.freedesktop.org/show_bug.cgi?id=102646
bug: https://bugs.freedesktop.org/show_bug.cgi?id=108941
bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1088
bug: https://gitlab.freedesktop.org/drm/amd/-/issues/628

Signed-off-by: Sergei Lopatin &lt;magist3r@gmail.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/i915/gt: Fill all the unused space in the GGTT</title>
<updated>2020-04-17T14:13:48+00:00</updated>
<author>
<name>Chris Wilson</name>
<email>chris@chris-wilson.co.uk</email>
</author>
<published>2020-03-31T15:23:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6880d00ea4c64a9f5d4f29fbe30cb8bfe635e804'/>
<id>6880d00ea4c64a9f5d4f29fbe30cb8bfe635e804</id>
<content type='text'>
[ Upstream commit 0b72a251bf92ca2378530fa1f9b35a71830ab51c ]

When we allocate space in the GGTT we may have to allocate a larger
region than will be populated by the object to accommodate fencing. Make
sure that this space beyond the end of the buffer points safely into
scratch space, in case the HW tries to access it anyway (e.g. fenced
access to the last tile row).

v2: Preemptively / conservatively guard gen6 ggtt as well.

Reported-by: Imre Deak &lt;imre.deak@intel.com&gt;
References: https://gitlab.freedesktop.org/drm/intel/-/issues/1554
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Matthew Auld &lt;matthew.auld@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Auld &lt;matthew.auld@intel.com&gt;
Reviewed-by: Imre Deak &lt;imre.deak@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200331152348.26946-1-chris@chris-wilson.co.uk
(cherry picked from commit 4d6c18590870fbac1e65dde5e01e621c8e0ca096)
Signed-off-by: Rodrigo Vivi &lt;rodrigo.vivi@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 0b72a251bf92ca2378530fa1f9b35a71830ab51c ]

When we allocate space in the GGTT we may have to allocate a larger
region than will be populated by the object to accommodate fencing. Make
sure that this space beyond the end of the buffer points safely into
scratch space, in case the HW tries to access it anyway (e.g. fenced
access to the last tile row).

v2: Preemptively / conservatively guard gen6 ggtt as well.

Reported-by: Imre Deak &lt;imre.deak@intel.com&gt;
References: https://gitlab.freedesktop.org/drm/intel/-/issues/1554
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Matthew Auld &lt;matthew.auld@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Auld &lt;matthew.auld@intel.com&gt;
Reviewed-by: Imre Deak &lt;imre.deak@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200331152348.26946-1-chris@chris-wilson.co.uk
(cherry picked from commit 4d6c18590870fbac1e65dde5e01e621c8e0ca096)
Signed-off-by: Rodrigo Vivi &lt;rodrigo.vivi@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/i915/ggtt: do not set bits 1-11 in gen12 ptes</title>
<updated>2020-04-17T14:13:48+00:00</updated>
<author>
<name>Daniele Ceraolo Spurio</name>
<email>daniele.ceraolospurio@intel.com</email>
</author>
<published>2020-02-26T18:56:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=79dbe6fbdd4606acabc9df266018046b75b62cdc'/>
<id>79dbe6fbdd4606acabc9df266018046b75b62cdc</id>
<content type='text'>
[ Upstream commit 69edc390a54268d41e45089cb972bf71510f5f07 ]

On TGL, bits 2-4 in the GGTT PTE are not ignored anymore and are
instead used for some extra VT-d capabilities. We don't (yet?) have
support for those capabilities, but, given that we shared the pte_encode
function betweed GGTT and PPGTT, we still set those bits to the PPGTT
PPAT values. The DMA engine gets very confused when those bits are
set while the iommu is enabled, leading to errors. E.g. when loading
the GuC we get:

[    9.796218] DMAR: DRHD: handling fault status reg 2
[    9.796235] DMAR: [DMA Write] Request device [00:02.0] PASID ffffffff fault addr 0 [fault reason 02] Present bit in context entry is clear
[    9.899215] [drm:intel_guc_fw_upload [i915]] *ERROR* GuC firmware signature verification failed

To fix this, just have dedicated gen8_pte_encode function per type of
gtt. Also, explicitly set vm-&gt;pte_encode for gen8_ppgtt, even if we
don't use it, to make sure we don't accidentally assign it to the GGTT
one, like we do for gen6_ppgtt, in case we need it in the future.

Reported-by: "Sodhi, Vunny" &lt;vunny.sodhi@intel.com&gt;
Signed-off-by: Daniele Ceraolo Spurio &lt;daniele.ceraolospurio@intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Cc: Matthew Auld &lt;matthew.auld@intel.com&gt;
Cc: Michal Wajdeczko &lt;michal.wajdeczko@intel.com&gt;
Reviewed-by: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200226185657.26445-1-daniele.ceraolospurio@intel.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 69edc390a54268d41e45089cb972bf71510f5f07 ]

On TGL, bits 2-4 in the GGTT PTE are not ignored anymore and are
instead used for some extra VT-d capabilities. We don't (yet?) have
support for those capabilities, but, given that we shared the pte_encode
function betweed GGTT and PPGTT, we still set those bits to the PPGTT
PPAT values. The DMA engine gets very confused when those bits are
set while the iommu is enabled, leading to errors. E.g. when loading
the GuC we get:

[    9.796218] DMAR: DRHD: handling fault status reg 2
[    9.796235] DMAR: [DMA Write] Request device [00:02.0] PASID ffffffff fault addr 0 [fault reason 02] Present bit in context entry is clear
[    9.899215] [drm:intel_guc_fw_upload [i915]] *ERROR* GuC firmware signature verification failed

To fix this, just have dedicated gen8_pte_encode function per type of
gtt. Also, explicitly set vm-&gt;pte_encode for gen8_ppgtt, even if we
don't use it, to make sure we don't accidentally assign it to the GGTT
one, like we do for gen6_ppgtt, in case we need it in the future.

Reported-by: "Sodhi, Vunny" &lt;vunny.sodhi@intel.com&gt;
Signed-off-by: Daniele Ceraolo Spurio &lt;daniele.ceraolospurio@intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Cc: Matthew Auld &lt;matthew.auld@intel.com&gt;
Cc: Michal Wajdeczko &lt;michal.wajdeczko@intel.com&gt;
Reviewed-by: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Signed-off-by: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200226185657.26445-1-daniele.ceraolospurio@intel.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu: fix gfx hang during suspend with video playback (v2)</title>
<updated>2020-04-17T14:13:47+00:00</updated>
<author>
<name>Prike Liang</name>
<email>Prike.Liang@amd.com</email>
</author>
<published>2020-04-07T12:21:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a1f57b87ddcc869b576aca73608f35cb436c3fdc'/>
<id>a1f57b87ddcc869b576aca73608f35cb436c3fdc</id>
<content type='text'>
[ Upstream commit 487eca11a321ef33bcf4ca5adb3c0c4954db1b58 ]

The system will be hang up during S3 suspend because of SMU is pending
for GC not respose the register CP_HQD_ACTIVE access request.This issue
root cause of accessing the GC register under enter GFX CGGPG and can
be fixed by disable GFX CGPG before perform suspend.

v2: Use disable the GFX CGPG instead of RLC safe mode guard.

Signed-off-by: Prike Liang &lt;Prike.Liang@amd.com&gt;
Tested-by: Mengbing Wang &lt;Mengbing.Wang@amd.com&gt;
Reviewed-by: Huang Rui &lt;ray.huang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
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 487eca11a321ef33bcf4ca5adb3c0c4954db1b58 ]

The system will be hang up during S3 suspend because of SMU is pending
for GC not respose the register CP_HQD_ACTIVE access request.This issue
root cause of accessing the GC register under enter GFX CGGPG and can
be fixed by disable GFX CGPG before perform suspend.

v2: Use disable the GFX CGPG instead of RLC safe mode guard.

Signed-off-by: Prike Liang &lt;Prike.Liang@amd.com&gt;
Tested-by: Mengbing Wang &lt;Mengbing.Wang@amd.com&gt;
Reviewed-by: Huang Rui &lt;ray.huang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/dp_mst: Fix clearing payload state on topology disable</title>
<updated>2020-04-17T14:13:47+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2020-01-22T19:43:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f9613df38f0804fac20fcf985d131cdb5c2ead41'/>
<id>f9613df38f0804fac20fcf985d131cdb5c2ead41</id>
<content type='text'>
[ Upstream commit 8732fe46b20c951493bfc4dba0ad08efdf41de81 ]

The issues caused by:

commit 64e62bdf04ab ("drm/dp_mst: Remove VCPI while disabling topology
mgr")

Prompted me to take a closer look at how we clear the payload state in
general when disabling the topology, and it turns out there's actually
two subtle issues here.

The first is that we're not grabbing &amp;mgr.payload_lock when clearing the
payloads in drm_dp_mst_topology_mgr_set_mst(). Seeing as the canonical
lock order is &amp;mgr.payload_lock -&gt; &amp;mgr.lock (because we always want
&amp;mgr.lock to be the inner-most lock so topology validation always
works), this makes perfect sense. It also means that -technically- there
could be racing between someone calling
drm_dp_mst_topology_mgr_set_mst() to disable the topology, along with a
modeset occurring that's modifying the payload state at the same time.

The second is the more obvious issue that Wayne Lin discovered, that
we're not clearing proposed_payloads when disabling the topology.

I actually can't see any obvious places where the racing caused by the
first issue would break something, and it could be that some of our
higher-level locks already prevent this by happenstance, but better safe
then sorry. So, let's make it so that drm_dp_mst_topology_mgr_set_mst()
first grabs &amp;mgr.payload_lock followed by &amp;mgr.lock so that we never
race when modifying the payload state. Then, we also clear
proposed_payloads to fix the original issue of enabling a new topology
with a dirty payload state. This doesn't clear any of the drm_dp_vcpi
structures, but those are getting destroyed along with the ports anyway.

Changes since v1:
* Use sizeof(mgr-&gt;payloads[0])/sizeof(mgr-&gt;proposed_vcpis[0]) instead -
  vsyrjala

Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200122194321.14953-1-lyude@redhat.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 8732fe46b20c951493bfc4dba0ad08efdf41de81 ]

The issues caused by:

commit 64e62bdf04ab ("drm/dp_mst: Remove VCPI while disabling topology
mgr")

Prompted me to take a closer look at how we clear the payload state in
general when disabling the topology, and it turns out there's actually
two subtle issues here.

The first is that we're not grabbing &amp;mgr.payload_lock when clearing the
payloads in drm_dp_mst_topology_mgr_set_mst(). Seeing as the canonical
lock order is &amp;mgr.payload_lock -&gt; &amp;mgr.lock (because we always want
&amp;mgr.lock to be the inner-most lock so topology validation always
works), this makes perfect sense. It also means that -technically- there
could be racing between someone calling
drm_dp_mst_topology_mgr_set_mst() to disable the topology, along with a
modeset occurring that's modifying the payload state at the same time.

The second is the more obvious issue that Wayne Lin discovered, that
we're not clearing proposed_payloads when disabling the topology.

I actually can't see any obvious places where the racing caused by the
first issue would break something, and it could be that some of our
higher-level locks already prevent this by happenstance, but better safe
then sorry. So, let's make it so that drm_dp_mst_topology_mgr_set_mst()
first grabs &amp;mgr.payload_lock followed by &amp;mgr.lock so that we never
race when modifying the payload state. Then, we also clear
proposed_payloads to fix the original issue of enabling a new topology
with a dirty payload state. This doesn't clear any of the drm_dp_vcpi
structures, but those are getting destroyed along with the ports anyway.

Changes since v1:
* Use sizeof(mgr-&gt;payloads[0])/sizeof(mgr-&gt;proposed_vcpis[0]) instead -
  vsyrjala

Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Reviewed-by: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200122194321.14953-1-lyude@redhat.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "drm/dp_mst: Remove VCPI while disabling topology mgr"</title>
<updated>2020-04-17T14:13:47+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2020-01-17T20:51:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a048bb435d30cd90a37be09de729c8b5882b22a4'/>
<id>a048bb435d30cd90a37be09de729c8b5882b22a4</id>
<content type='text'>
[ Upstream commit a86675968e2300fb567994459da3dbc4cd1b322a ]

This reverts commit 64e62bdf04ab8529f45ed0a85122c703035dec3a.

This commit ends up causing some lockdep splats due to trying to grab the
payload lock while holding the mgr's lock:

[   54.010099]
[   54.011765] ======================================================
[   54.018670] WARNING: possible circular locking dependency detected
[   54.025577] 5.5.0-rc6-02274-g77381c23ee63 #47 Not tainted
[   54.031610] ------------------------------------------------------
[   54.038516] kworker/1:6/1040 is trying to acquire lock:
[   54.044354] ffff888272af3228 (&amp;mgr-&gt;payload_lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.054957]
[   54.054957] but task is already holding lock:
[   54.061473] ffff888272af3060 (&amp;mgr-&gt;lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.071193]
[   54.071193] which lock already depends on the new lock.
[   54.071193]
[   54.080334]
[   54.080334] the existing dependency chain (in reverse order) is:
[   54.088697]
[   54.088697] -&gt; #1 (&amp;mgr-&gt;lock){+.+.}:
[   54.094440]        __mutex_lock+0xc3/0x498
[   54.099015]        drm_dp_mst_topology_get_port_validated+0x25/0x80
[   54.106018]        drm_dp_update_payload_part1+0xa2/0x2e2
[   54.112051]        intel_mst_pre_enable_dp+0x144/0x18f
[   54.117791]        intel_encoders_pre_enable+0x63/0x70
[   54.123532]        hsw_crtc_enable+0xa1/0x722
[   54.128396]        intel_update_crtc+0x50/0x194
[   54.133455]        skl_commit_modeset_enables+0x40c/0x540
[   54.139485]        intel_atomic_commit_tail+0x5f7/0x130d
[   54.145418]        intel_atomic_commit+0x2c8/0x2d8
[   54.150770]        drm_atomic_helper_set_config+0x5a/0x70
[   54.156801]        drm_mode_setcrtc+0x2ab/0x833
[   54.161862]        drm_ioctl+0x2e5/0x424
[   54.166242]        vfs_ioctl+0x21/0x2f
[   54.170426]        do_vfs_ioctl+0x5fb/0x61e
[   54.175096]        ksys_ioctl+0x55/0x75
[   54.179377]        __x64_sys_ioctl+0x1a/0x1e
[   54.184146]        do_syscall_64+0x5c/0x6d
[   54.188721]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   54.194946]
[   54.194946] -&gt; #0 (&amp;mgr-&gt;payload_lock){+.+.}:
[   54.201463]
[   54.201463] other info that might help us debug this:
[   54.201463]
[   54.210410]  Possible unsafe locking scenario:
[   54.210410]
[   54.217025]        CPU0                    CPU1
[   54.222082]        ----                    ----
[   54.227138]   lock(&amp;mgr-&gt;lock);
[   54.230643]                                lock(&amp;mgr-&gt;payload_lock);
[   54.237742]                                lock(&amp;mgr-&gt;lock);
[   54.244062]   lock(&amp;mgr-&gt;payload_lock);
[   54.248346]
[   54.248346]  *** DEADLOCK ***
[   54.248346]
[   54.254959] 7 locks held by kworker/1:6/1040:
[   54.259822]  #0: ffff888275c4f528 ((wq_completion)events){+.+.},
at: worker_thread+0x455/0x6e2
[   54.269451]  #1: ffffc9000119beb0
((work_completion)(&amp;(&amp;dev_priv-&gt;hotplug.hotplug_work)-&gt;work)){+.+.},
at: worker_thread+0x455/0x6e2
[   54.282768]  #2: ffff888272a403f0 (&amp;dev-&gt;mode_config.mutex){+.+.},
at: i915_hotplug_work_func+0x4b/0x2be
[   54.293368]  #3: ffffffff824fc6c0 (drm_connector_list_iter){.+.+},
at: i915_hotplug_work_func+0x17e/0x2be
[   54.304061]  #4: ffffc9000119bc58 (crtc_ww_class_acquire){+.+.},
at: drm_helper_probe_detect_ctx+0x40/0xfd
[   54.314855]  #5: ffff888272a40470 (crtc_ww_class_mutex){+.+.}, at:
drm_modeset_lock+0x74/0xe2
[   54.324385]  #6: ffff888272af3060 (&amp;mgr-&gt;lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.334597]
[   54.334597] stack backtrace:
[   54.339464] CPU: 1 PID: 1040 Comm: kworker/1:6 Not tainted
5.5.0-rc6-02274-g77381c23ee63 #47
[   54.348893] Hardware name: Google Fizz/Fizz, BIOS
Google_Fizz.10139.39.0 01/04/2018
[   54.357451] Workqueue: events i915_hotplug_work_func
[   54.362995] Call Trace:
[   54.365724]  dump_stack+0x71/0x9c
[   54.369427]  check_noncircular+0x91/0xbc
[   54.373809]  ? __lock_acquire+0xc9e/0xf66
[   54.378286]  ? __lock_acquire+0xc9e/0xf66
[   54.382763]  ? lock_acquire+0x175/0x1ac
[   54.387048]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.393177]  ? __mutex_lock+0xc3/0x498
[   54.397362]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.403492]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.409620]  ? drm_dp_dpcd_access+0xd9/0x101
[   54.414390]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.420517]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.426645]  ? intel_digital_port_connected+0x34d/0x35c
[   54.432482]  ? intel_dp_detect+0x227/0x44e
[   54.437056]  ? ww_mutex_lock+0x49/0x9a
[   54.441242]  ? drm_helper_probe_detect_ctx+0x75/0xfd
[   54.446789]  ? intel_encoder_hotplug+0x4b/0x97
[   54.451752]  ? intel_ddi_hotplug+0x61/0x2e0
[   54.456423]  ? mark_held_locks+0x53/0x68
[   54.460803]  ? _raw_spin_unlock_irqrestore+0x3a/0x51
[   54.466347]  ? lockdep_hardirqs_on+0x187/0x1a4
[   54.471310]  ? drm_connector_list_iter_next+0x89/0x9a
[   54.476953]  ? i915_hotplug_work_func+0x206/0x2be
[   54.482208]  ? worker_thread+0x4d5/0x6e2
[   54.486587]  ? worker_thread+0x455/0x6e2
[   54.490966]  ? queue_work_on+0x64/0x64
[   54.495151]  ? kthread+0x1e9/0x1f1
[   54.498946]  ? queue_work_on+0x64/0x64
[   54.503130]  ? kthread_unpark+0x5e/0x5e
[   54.507413]  ? ret_from_fork+0x3a/0x50

The proper fix for this is probably cleanup the VCPI allocations when we're
enabling the topology, or on the first payload allocation. For now though,
let's just revert.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Fixes: 64e62bdf04ab ("drm/dp_mst: Remove VCPI while disabling topology mgr")
Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Reviewed-by: Sean Paul &lt;sean@poorly.run&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200117205149.97262-1-lyude@redhat.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 a86675968e2300fb567994459da3dbc4cd1b322a ]

This reverts commit 64e62bdf04ab8529f45ed0a85122c703035dec3a.

This commit ends up causing some lockdep splats due to trying to grab the
payload lock while holding the mgr's lock:

[   54.010099]
[   54.011765] ======================================================
[   54.018670] WARNING: possible circular locking dependency detected
[   54.025577] 5.5.0-rc6-02274-g77381c23ee63 #47 Not tainted
[   54.031610] ------------------------------------------------------
[   54.038516] kworker/1:6/1040 is trying to acquire lock:
[   54.044354] ffff888272af3228 (&amp;mgr-&gt;payload_lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.054957]
[   54.054957] but task is already holding lock:
[   54.061473] ffff888272af3060 (&amp;mgr-&gt;lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.071193]
[   54.071193] which lock already depends on the new lock.
[   54.071193]
[   54.080334]
[   54.080334] the existing dependency chain (in reverse order) is:
[   54.088697]
[   54.088697] -&gt; #1 (&amp;mgr-&gt;lock){+.+.}:
[   54.094440]        __mutex_lock+0xc3/0x498
[   54.099015]        drm_dp_mst_topology_get_port_validated+0x25/0x80
[   54.106018]        drm_dp_update_payload_part1+0xa2/0x2e2
[   54.112051]        intel_mst_pre_enable_dp+0x144/0x18f
[   54.117791]        intel_encoders_pre_enable+0x63/0x70
[   54.123532]        hsw_crtc_enable+0xa1/0x722
[   54.128396]        intel_update_crtc+0x50/0x194
[   54.133455]        skl_commit_modeset_enables+0x40c/0x540
[   54.139485]        intel_atomic_commit_tail+0x5f7/0x130d
[   54.145418]        intel_atomic_commit+0x2c8/0x2d8
[   54.150770]        drm_atomic_helper_set_config+0x5a/0x70
[   54.156801]        drm_mode_setcrtc+0x2ab/0x833
[   54.161862]        drm_ioctl+0x2e5/0x424
[   54.166242]        vfs_ioctl+0x21/0x2f
[   54.170426]        do_vfs_ioctl+0x5fb/0x61e
[   54.175096]        ksys_ioctl+0x55/0x75
[   54.179377]        __x64_sys_ioctl+0x1a/0x1e
[   54.184146]        do_syscall_64+0x5c/0x6d
[   54.188721]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   54.194946]
[   54.194946] -&gt; #0 (&amp;mgr-&gt;payload_lock){+.+.}:
[   54.201463]
[   54.201463] other info that might help us debug this:
[   54.201463]
[   54.210410]  Possible unsafe locking scenario:
[   54.210410]
[   54.217025]        CPU0                    CPU1
[   54.222082]        ----                    ----
[   54.227138]   lock(&amp;mgr-&gt;lock);
[   54.230643]                                lock(&amp;mgr-&gt;payload_lock);
[   54.237742]                                lock(&amp;mgr-&gt;lock);
[   54.244062]   lock(&amp;mgr-&gt;payload_lock);
[   54.248346]
[   54.248346]  *** DEADLOCK ***
[   54.248346]
[   54.254959] 7 locks held by kworker/1:6/1040:
[   54.259822]  #0: ffff888275c4f528 ((wq_completion)events){+.+.},
at: worker_thread+0x455/0x6e2
[   54.269451]  #1: ffffc9000119beb0
((work_completion)(&amp;(&amp;dev_priv-&gt;hotplug.hotplug_work)-&gt;work)){+.+.},
at: worker_thread+0x455/0x6e2
[   54.282768]  #2: ffff888272a403f0 (&amp;dev-&gt;mode_config.mutex){+.+.},
at: i915_hotplug_work_func+0x4b/0x2be
[   54.293368]  #3: ffffffff824fc6c0 (drm_connector_list_iter){.+.+},
at: i915_hotplug_work_func+0x17e/0x2be
[   54.304061]  #4: ffffc9000119bc58 (crtc_ww_class_acquire){+.+.},
at: drm_helper_probe_detect_ctx+0x40/0xfd
[   54.314855]  #5: ffff888272a40470 (crtc_ww_class_mutex){+.+.}, at:
drm_modeset_lock+0x74/0xe2
[   54.324385]  #6: ffff888272af3060 (&amp;mgr-&gt;lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.334597]
[   54.334597] stack backtrace:
[   54.339464] CPU: 1 PID: 1040 Comm: kworker/1:6 Not tainted
5.5.0-rc6-02274-g77381c23ee63 #47
[   54.348893] Hardware name: Google Fizz/Fizz, BIOS
Google_Fizz.10139.39.0 01/04/2018
[   54.357451] Workqueue: events i915_hotplug_work_func
[   54.362995] Call Trace:
[   54.365724]  dump_stack+0x71/0x9c
[   54.369427]  check_noncircular+0x91/0xbc
[   54.373809]  ? __lock_acquire+0xc9e/0xf66
[   54.378286]  ? __lock_acquire+0xc9e/0xf66
[   54.382763]  ? lock_acquire+0x175/0x1ac
[   54.387048]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.393177]  ? __mutex_lock+0xc3/0x498
[   54.397362]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.403492]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.409620]  ? drm_dp_dpcd_access+0xd9/0x101
[   54.414390]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.420517]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.426645]  ? intel_digital_port_connected+0x34d/0x35c
[   54.432482]  ? intel_dp_detect+0x227/0x44e
[   54.437056]  ? ww_mutex_lock+0x49/0x9a
[   54.441242]  ? drm_helper_probe_detect_ctx+0x75/0xfd
[   54.446789]  ? intel_encoder_hotplug+0x4b/0x97
[   54.451752]  ? intel_ddi_hotplug+0x61/0x2e0
[   54.456423]  ? mark_held_locks+0x53/0x68
[   54.460803]  ? _raw_spin_unlock_irqrestore+0x3a/0x51
[   54.466347]  ? lockdep_hardirqs_on+0x187/0x1a4
[   54.471310]  ? drm_connector_list_iter_next+0x89/0x9a
[   54.476953]  ? i915_hotplug_work_func+0x206/0x2be
[   54.482208]  ? worker_thread+0x4d5/0x6e2
[   54.486587]  ? worker_thread+0x455/0x6e2
[   54.490966]  ? queue_work_on+0x64/0x64
[   54.495151]  ? kthread+0x1e9/0x1f1
[   54.498946]  ? queue_work_on+0x64/0x64
[   54.503130]  ? kthread_unpark+0x5e/0x5e
[   54.507413]  ? ret_from_fork+0x3a/0x50

The proper fix for this is probably cleanup the VCPI allocations when we're
enabling the topology, or on the first payload allocation. For now though,
let's just revert.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Fixes: 64e62bdf04ab ("drm/dp_mst: Remove VCPI while disabling topology mgr")
Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Reviewed-by: Sean Paul &lt;sean@poorly.run&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200117205149.97262-1-lyude@redhat.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
