On Sun, Feb 11, 2018 at 10:38:28AM +0100, Lukas Wunner wrote: > [...] > i915, malidp and msm "solved" this issue by not stopping the poll worker > on runtime suspend. But this results in the GPU bouncing back and forth > between D0 and D3 continuously. That's a total no-go for GPUs which > runtime suspend to D3cold since every suspend/resume cycle costs a > significant amount of time and energy. (i915 and malidp do not seem > to acquire a runtime PM ref in the ->detect callbacks, which seems > questionable. msm however does and would also deadlock if it disabled > the poll worker on runtime suspend. cc += Archit, Liviu, intel-gfx)
In i915 polling is on during runtime suspend only if there are outputs without hotplug interrupt support. A special case is when an output has working HPD interrupts when in D0, but no interrupts when runtime suspended. For these we start polling (from a scheduled work) in the runtime suspend hook and stop it in the runtime resume hook (again from a scheduled work). Imo whether to leave polling on or not for the above purpose is a policy question (configurable with the drm_kms_helper.poll param). --Imre > > Please review. Thanks, > > Lukas > > Lukas Wunner (5): > workqueue: Allow retrieval of current task's work struct > drm: Allow determining if current task is output poll worker > drm/nouveau: Fix deadlock on runtime suspend > drm/radeon: Fix deadlock on runtime suspend > drm/amdgpu: Fix deadlock on runtime suspend > > drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 58 +++++++++++++------- > drivers/gpu/drm/drm_probe_helper.c | 14 +++++ > drivers/gpu/drm/nouveau/nouveau_connector.c | 18 +++++-- > drivers/gpu/drm/radeon/radeon_connectors.c | 74 > +++++++++++++++++--------- > include/drm/drm_crtc_helper.h | 1 + > include/linux/workqueue.h | 1 + > kernel/workqueue.c | 16 ++++++ > 7 files changed, 132 insertions(+), 50 deletions(-) > > -- > 2.15.1 > > _______________________________________________ > dri-devel mailing list > dri-de...@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
