https://github.com/torvalds/linux
Revision 688f3d1ebedffa310b6591bd1b63fa0770d945fe authored by Lyude Paul on 20 June 2019, 23:21:26 UTC, committed by Alex Deucher on 01 July 2019, 14:15:00 UTC
I'm not entirely sure why this is, but for some reason:
921935dc6404 ("drm/amd/powerplay: enforce display related settings only on needed")
Breaks runtime PM resume on the Radeon PRO WX 3100 (Lexa) in one the
pre-production laptops I have. The issue manifests as the following
messages in dmesg:
[drm] UVD and UVD ENC initialized successfully.
amdgpu 0000:3b:00.0: [drm:amdgpu_ring_test_helper [amdgpu]] *ERROR* ring vce1 test failed (-110)
[drm:amdgpu_device_ip_resume_phase2 [amdgpu]] *ERROR* resume of IP block <vce_v3_0> failed -110
[drm:amdgpu_device_resume [amdgpu]] *ERROR* amdgpu_device_ip_resume failed (-110).
And happens after about 6-10 runtime PM suspend/resume cycles (sometimes
sooner, if you're lucky!). Unfortunately I can't seem to pin down
precisely which part in psm_adjust_power_state_dynamic that is causing
the issue, but not skipping the display setting setup seems to fix it.
Hopefully if there is a better fix for this, this patch will spark
discussion around it.
Fixes: 921935dc6404 ("drm/amd/powerplay: enforce display related settings only on needed")
Cc: Evan Quan <evan.quan@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Rex Zhu <Rex.Zhu@amd.com>
Cc: Likun Gao <Likun.Gao@amd.com>
Cc: <stable@vger.kernel.org> # v5.1+
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 parent f78c581
Tip revision: 688f3d1ebedffa310b6591bd1b63fa0770d945fe authored by Lyude Paul on 20 June 2019, 23:21:26 UTC
drm/amdgpu: Don't skip display settings in hwmgr_resume()
drm/amdgpu: Don't skip display settings in hwmgr_resume()
Tip revision: 688f3d1
percpu-rw-semaphore.txt
====================
Percpu rw semaphores
====================
Percpu rw semaphores is a new read-write semaphore design that is
optimized for locking for reading.
The problem with traditional read-write semaphores is that when multiple
cores take the lock for reading, the cache line containing the semaphore
is bouncing between L1 caches of the cores, causing performance
degradation.
Locking for reading is very fast, it uses RCU and it avoids any atomic
instruction in the lock and unlock path. On the other hand, locking for
writing is very expensive, it calls synchronize_rcu() that can take
hundreds of milliseconds.
The lock is declared with "struct percpu_rw_semaphore" type.
The lock is initialized percpu_init_rwsem, it returns 0 on success and
-ENOMEM on allocation failure.
The lock must be freed with percpu_free_rwsem to avoid memory leak.
The lock is locked for read with percpu_down_read, percpu_up_read and
for write with percpu_down_write, percpu_up_write.
The idea of using RCU for optimized rw-lock was introduced by
Eric Dumazet <eric.dumazet@gmail.com>.
The code was written by Mikulas Patocka <mpatocka@redhat.com>
Computing file changes ...
