From: Pengyu Luo <mitltlatltl@gmail.com>
Date: Sat, 7 Mar 2026 11:12:49 +0000 (+0800)
Subject: drm/msm/dsi: fix hdisplay calculation for CMD mode panel
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=82159db4371f5cef56444ebd0b8f96e2a6d709ff;p=thirdparty%2Fkernel%2Fstable.git

drm/msm/dsi: fix hdisplay calculation for CMD mode panel

Commit ac47870fd795 ("drm/msm/dsi: fix hdisplay calculation when
programming dsi registers") incorrecly broke hdisplay calculation for
CMD mode by specifying incorrect number of bytes per transfer, fix it.

Fixes: ac47870fd795 ("drm/msm/dsi: fix hdisplay calculation when programming dsi registers")
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/709917/
Link: https://lore.kernel.org/r/20260307111250.105772-2-mitltlatltl@gmail.com
[DB: fixed commit message]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 3efcc3f6c381..1c0841a1c101 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1034,8 +1034,9 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 		/*
 		 * DPU sends 3 bytes per pclk cycle to DSI. If widebus is
 		 * enabled, MDP always sends out 48-bit compressed data per
-		 * pclk and on average, DSI consumes an amount of compressed
-		 * data equivalent to the uncompressed pixel depth per pclk.
+		 * pclk and on average, for video mode, DSI consumes only an
+		 * amount of compressed data equivalent to the uncompressed
+		 * pixel depth per pclk.
 		 *
 		 * Calculate the number of pclks needed to transmit one line of
 		 * the compressed data.
@@ -1047,10 +1048,14 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 		 * unused anyway.
 		 */
 		h_total -= hdisplay;
-		if (wide_bus_enabled)
-			bits_per_pclk = dsc->bits_per_component * 3;
-		else
+		if (wide_bus_enabled) {
+			if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO)
+				bits_per_pclk = dsc->bits_per_component * 3;
+			else
+				bits_per_pclk = 48;
+		} else {
 			bits_per_pclk = 24;
+		}
 
 		hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc) * 8, bits_per_pclk);