[Intel-gfx] [RFC 2/2] drm/i915/display: Protect pipe_update against dc3co exit

[Anshuman Gupta]

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 at intel.com>
Cc: <stable at vger.kernel.org>
Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index ba26545392bc..3b81b98c0daf 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -15924,6 +15924,8 @@ static void intel_update_crtc(struct intel_atomic_state *state,
 	else
 		intel_fbc_enable(state, crtc);
 
+	/* Protect intel_pipe_update_{start,end} with power_domians lock */
+	mutex_lock(&dev_priv->power_domains.lock);
 	/* Perform vblank evasion around commit operation */
 	intel_pipe_update_start(new_crtc_state);
 
@@ -15935,6 +15937,7 @@ static void intel_update_crtc(struct intel_atomic_state *state,
 		i9xx_update_planes_on_crtc(state, crtc);
 
 	intel_pipe_update_end(new_crtc_state);
+	mutex_unlock(&dev_prive->power_domains.lock);
 
 	/*
 	 * We usually enable FIFO underrun interrupts as part of the
-- 
2.26.2