[Intel-gfx] [PATCH v6 8/9] drm/i915: Force PSR1 exit when getting pipe CRC

[José Roberto de Souza]

If PSR1 is active when pipe CRC is enabled the CRC calculations will
be inhibit by the transition to low power states that PSR1 brings.
So lets force a PSR1 exit and as soon as pipe CRC is enabled it will
block PSR1 activation and avoid CRC timeouts when running IGT tests.

There is a little window between the call to force exit PSR and the
write to pipe CRC registers that needs to happen within the minimum
of 6 idles frames otherwise PSR1 will be active again causing the CRC
timeouts but anyways this will at least reduce the occurrence of CRC
timeouts.

This can possibily fix issues present right now but I did not found
any open, I mostly got this issue from previous CI runs of this
series, bellow some exambles:

* igt at kms_color@pipe-b-ctm-0-75:
- shard-apl:          PASS -> FAIL +9

* igt at kms_cursor_legacy@flip-vs-cursor-busy-crc-legacy:
- shard-apl:          PASS -> DMESG-FAIL +17

* igt at kms_frontbuffer_tracking@fbc-1p-primscrn-indfb-pgflip-blt:
- shard-kbl:          PASS -> DMESG-FAIL +12

* igt at kms_pipe_crc_basic@read-crc-pipe-c:
- shard-kbl:          PASS -> FAIL +7

v6: s/PSR/PSR1 (Dhinakaran)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/intel_psr.c | 36 ++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 9847f6b0cd9a..053dbba6abde 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -452,6 +452,7 @@ static void hsw_activate_psr1(struct intel_dp *intel_dp)
 	 * frames, we'll go with 9 frames for now
 	 */
 	idle_frames = max(idle_frames, dev_priv->psr.sink_sync_latency + 1);
+
 	val |= idle_frames << EDP_PSR_IDLE_FRAME_SHIFT;
 
 	val |= max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT;
@@ -853,6 +854,20 @@ void intel_psr_disable(struct intel_dp *intel_dp,
 	cancel_work_sync(&dev_priv->psr.work);
 }
 
+static void psr_force_hw_tracking_exit(struct drm_i915_private *dev_priv)
+{
+	/*
+	 * Display WA #0884: all
+	 * This documented WA for bxt can be safely applied
+	 * broadly so we can force HW tracking to exit PSR
+	 * instead of disabling and re-enabling.
+	 * Workaround tells us to write 0 to CUR_SURFLIVE_A,
+	 * but it makes more sense write to the current active
+	 * pipe.
+	 */
+	I915_WRITE(CURSURFLIVE(dev_priv->psr.pipe), 0);
+}
+
 /**
  * intel_psr_update - Update PSR state
  * @intel_dp: Intel DP
@@ -877,8 +892,13 @@ void intel_psr_update(struct intel_dp *intel_dp,
 	enable = crtc_state->has_psr && psr_global_enabled(psr->debug);
 	psr2_enable = intel_psr2_enabled(dev_priv, crtc_state);
 
-	if (enable == psr->enabled && psr2_enable == psr->psr2_enabled)
+	if (enable == psr->enabled && psr2_enable == psr->psr2_enabled) {
+		/* Force a PSR exit when enabling CRC to avoid CRC timeouts */
+		if (crtc_state->crc_enabled && psr->enabled)
+			psr_force_hw_tracking_exit(dev_priv);
+
 		goto unlock;
+	}
 
 	if (psr->enabled)
 		intel_psr_disable_locked(intel_dp);
@@ -1148,18 +1168,8 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
 	dev_priv->psr.busy_frontbuffer_bits &= ~frontbuffer_bits;
 
 	/* By definition flush = invalidate + flush */
-	if (frontbuffer_bits) {
-		/*
-		 * Display WA #0884: all
-		 * This documented WA for bxt can be safely applied
-		 * broadly so we can force HW tracking to exit PSR
-		 * instead of disabling and re-enabling.
-		 * Workaround tells us to write 0 to CUR_SURFLIVE_A,
-		 * but it makes more sense write to the current active
-		 * pipe.
-		 */
-		I915_WRITE(CURSURFLIVE(dev_priv->psr.pipe), 0);
-	}
+	if (frontbuffer_bits)
+		psr_force_hw_tracking_exit(dev_priv);
 
 	if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
 		schedule_work(&dev_priv->psr.work);
-- 
2.21.0