This is a note to let you know that I've just added the patch titled
drm/msm/dsi: Use DSC slice(s) packet size to compute word count
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-msm-dsi-use-dsc-slice-s-packet-size-to-compute-w.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 89313b0ea2508e25ab66f171639b86a8ecfeddb9
Author: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
Date: Thu Dec 22 00:19:37 2022 +0100
drm/msm/dsi: Use DSC slice(s) packet size to compute word count
[ Upstream commit bc6b6ff8135c4b96787eda88f3baf653939a75ce ]
According to downstream the value to use for WORD_COUNT is
bytes_per_pkt, which denotes the number of bytes in a packet based on
how many slices have been configured by the panel driver times the
width of a slice times the number of bytes per pixel.
The DSC panels seen thus far use one byte per pixel, only one slice
per packet, and a slice width of half the panel width leading to the
desired bytes_per_pkt+1 value to be equal to hdisplay/2+1. This however
isn't the case anymore for panels that configure two slices per packet,
where the value should now be hdisplay+1.
Note that the aforementioned panel (on a Sony Xperia XZ3, sdm845) with
slice_count=1 has also been tested to successfully accept slice_count=2,
which would have shown corrupted output previously.
Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Patchwork: https://patchwork.freedesktop.org/patch/515694/
Link: https://lore.kernel.org/r/20221221231943.1961117-3-marijn.suijten@xxxxxxxxxxxxxx
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Stable-dep-of: 155fa3a91d64 ("drm/msm/dsi: Remove incorrect references to slice_count")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index f167a45f1fbdd..5ab5e872c3cf1 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -987,7 +987,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
if (!msm_host->dsc)
wc = hdisplay * dsi_get_bpp(msm_host->format) / 8 + 1;
else
- wc = mode->hdisplay / 2 + 1;
+ wc = msm_host->dsc->slice_chunk_size * msm_host->dsc->slice_count + 1;
dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL,
DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) |
