On Fri, Dec 04, 2020 at 01:40:03PM +0530, Anshuman Gupta wrote:
On 2020-11-30 at 17:28:32 +0200, Imre Deak wrote:
On Mon, Nov 30, 2020 at 02:46:46PM +0530, Anshuman Gupta wrote:
At usual case DC3CO exit happen automatically by DMC f/w whenever PSR2 clears idle. This happens smoothly by DMC f/w to work with flips. But there are certain scenario where DC3CO Disallowed by driver asynchronous with flips. In such scenario display engine could be already in DC3CO state and driver has disallowed it, It initiates DC3CO exit sequence in DMC f/w which requires a dc3co exit delay of 200us in driver. It requires to protect intel_pipe_update_{update_end} with dc3co exit delay.
Cc: Imre Deak imre.deak@intel.com Cc: stable@vger.kernel.org Signed-off-by: Anshuman Gupta anshuman.gupta@intel.com
To make sure that it doesn't hide the root cause (or affects unrelated platforms), I'd only add locking around DC3co changes with a new lock, using lock/unlock helpers in intel_display_power.c called from intel_pipe_update_start/end.
Also please submit this patch separately, w/o the optimization in patch 1/2, so we know that this change fixes the problem.
This patch doesn't seems to fix the issue. Looks like there is some other set of display register updates before completing the dc3co exit delay beyond intel_pipe_update_start/end causing this issue.
Not really sure I understand the DC3CO issue here, nor how grabbing a mutex across the update could help.
But anyways, maybe we should just: diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 2e2dd746921f..96276f0feddc 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -16268,8 +16268,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
drm_atomic_helper_wait_for_dependencies(&state->base);
- if (state->modeset) - wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_MODESET); + wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_MODESET);
for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) { @@ -16415,8 +16414,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state) * the culprit. */ intel_uncore_arm_unclaimed_mmio_detection(&dev_priv->uncore); - intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET, wakeref); } + intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET, wakeref); intel_runtime_pm_put(&dev_priv->runtime_pm, state->wakeref);
/*
To get the DMC out of equation entirely for all plane updates?