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* [Intel-gfx] [PATCH v1] drm/i915: Clamp min_cdclk to max_cdclk_freq to unblock 8K
@ 2020-06-30 11:26 Stanislav Lisovskiy
  2020-06-30 15:56 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 10+ messages in thread
From: Stanislav Lisovskiy @ 2020-06-30 11:26 UTC (permalink / raw)
  To: intel-gfx

We still need "Bump up CDCLK" workaround otherwise getting
underruns - however currently it blocks 8K as CDCLK = Pixel rate,
in 8K case would require CDCLK to be around 1 Ghz which is not
possible.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cdclk.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 45f7f33d1144..01a5bc6b08c4 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -2080,9 +2080,21 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
 	 * Explicitly stating here that this seems to be currently
 	 * rather a Hack, than final solution.
 	 */
-	if (IS_TIGERLAKE(dev_priv))
+	if (IS_TIGERLAKE(dev_priv)) {
 		min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate);
 
+		/*
+		 * Clamp to max_cdclk_freq in order not to break an 8K,
+		 * but still leave W/A at place.
+		 */
+		min_cdclk = min(min_cdclk, (int)dev_priv->max_cdclk_freq);
+
+		/*
+		 * max_cdclk_freq check obviously not needed - just return.
+		 */
+		return min_cdclk;
+	}
+
 	if (min_cdclk > dev_priv->max_cdclk_freq) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "required cdclk (%d kHz) exceeds max (%d kHz)\n",
-- 
2.24.1.485.gad05a3d8e5

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^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2020-07-01 19:13 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-30 11:26 [Intel-gfx] [PATCH v1] drm/i915: Clamp min_cdclk to max_cdclk_freq to unblock 8K Stanislav Lisovskiy
2020-06-30 15:56 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2020-06-30 16:19 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-06-30 16:29 ` [Intel-gfx] [PATCH v1] " Ville Syrjälä
2020-06-30 20:27   ` Manasi Navare
2020-07-01  5:57   ` Lisovskiy, Stanislav
2020-06-30 21:17 ` [Intel-gfx] ✓ Fi.CI.IGT: success for " Patchwork
2020-07-01 12:20 ` [Intel-gfx] [PATCH v1] " Maarten Lankhorst
2020-07-01 18:44   ` Manasi Navare
2020-07-01 19:13     ` Lisovskiy, Stanislav

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