On 25-06-2025 22:59, Imre Deak wrote:
On Wed, Jun 25, 2025 at 11:04:07AM +0530, Arun R Murthy wrote:
Use recommended values as per wa_14021694213 to compare with the
calculated value and choose minimum of them.
v2: corrected checkpatch warning and retain the restriction for
min_hblank (Jani)
v3: use calculated value to compare with recomended value and choose
minimum of them (Imre)
Bspec: 74379
Signed-off-by: Arun R Murthy <arun.r.mur...@intel.com>
---
Changes in v3:
- EDITME: describe what is new in this series revision.
- EDITME: use bulletpoints and terse descriptions.
- Link to v2:
https://lore.kernel.org/r/20250624-min_hblank-v2-1-9110a9342...@intel.com
Changes in v2:
- EDITME: describe what is new in this series revision.
- EDITME: use bulletpoints and terse descriptions.
- Link to v1:
https://lore.kernel.org/r/20250624-min_hblank-v1-1-5c100e4a8...@intel.com
The above 'Changes in vx' templates could be removed imo.
---
drivers/gpu/drm/i915/display/intel_dp.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
b/drivers/gpu/drm/i915/display/intel_dp.c
index
f48912f308df7fd26c9d089e8f1bd096bfc8df95..c55315fb74734fded40695bae40dd19f71a9786f
100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3175,7 +3175,22 @@ int intel_dp_compute_min_hblank(struct intel_crtc_state
*crtc_state,
*/
min_hblank = min_hblank - 2;
- min_hblank = min(10, min_hblank);
+ /*
+ * min_hblank formula is undergoing a change, to avoid underrun use the
+ * recomended value in spec to compare with the calculated one and use
the
+ * minimum value
+ */
+ if (intel_dp_is_uhbr(crtc_state)) {
+ if (crtc_state->dsc.compression_enable &&
+ crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 &&
+ crtc_state->pipe_bpp == 18)
The bspec page describes this format as YUV420 at 6 bpp. Not sure how
that would align with pipe_bpp == 18 (which is 6 _bpc_). Bspec could
also refer to the compressed bpp, however the driver's minimum
compressed bpp is 8. Could you clarify which bpp bspec refers to?
Here since the check if for DSC, its compressed bpp and even though
driver's minimum bpc is 8 as per the calculations for bpc 6 min_hblank
should be 2.
Thanks and Regards,
Arun R Murthy
-------------------
+ min_hblank = min(2, min_hblank);
+ else
+ min_hblank = min(3, min_hblank);
+ } else {
+ min_hblank = min(10, min_hblank);
+ }
+
crtc_state->min_hblank = min_hblank;
return 0;
---
base-commit: da56936fad6f5e1d5f0cef8b50277bfb071eefe7
change-id: 20250624-min_hblank-8af8d2626ff8
Best regards,
--
Arun R Murthy <arun.r.mur...@intel.com>
