On 12/5/2020 2:28 AM, Manasi Navare wrote:
This patch fixes the slice count computation algorithm
for calculating the slice count based on Peak pixel rate
and the max slice width allowed on the DSC engines.
We need to ensure slice count > min slice count req
as per DP spec based on peak pixel rate and that it is
greater than min slice count based on the max slice width
advertised by DPCD. So use max of these two.
In the prev patch we were using min of these 2 causing it
to violate the max slice width limitation causing a blank
screen on 8K@60.
Fixes: d9218c8f6cf4 ("drm/i915/dp: Add helpers for Compressed BPP and Slice Count for DSC")
Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 2d4d5e95af84..cb5e42c3ecd5 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -615,7 +615,7 @@ static u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
return 0;
}
/* Also take into account max slice width */
- min_slice_count = min_t(u8, min_slice_count,
+ min_slice_count = max_t(u8, min_slice_count,
DIV_ROUND_UP(mode_hdisplay,
max_slice_width));
Change looks good to me.
'min_slice_count' is essentially the least no. of slices that would be
sufficient. So max of the two values would be correct.
Also tested with this change on an 8k panel, we are able get 8 DSC
slices with this change, which is correct for 8k@60 resolution.
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
