2024-04-03 09:21:23

by Jun Nie

[permalink] [raw]
Subject: [PATCH v3 4/6] drm/msm/dsi: add a comment to explain pkt_per_line encoding

From: Jonathan Marek <[email protected]>

Make it clear why the pkt_per_line value is being "divided by 2".

Signed-off-by: Jonathan Marek <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Jun Nie <[email protected]>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 80ea4f1d8274..b0507a42ee6a 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -886,7 +886,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
/* DSI_VIDEO_COMPRESSION_MODE & DSI_COMMAND_COMPRESSION_MODE
* registers have similar offsets, so for below common code use
* DSI_VIDEO_COMPRESSION_MODE_XXXX for setting bits
+ *
+ * pkt_per_line is log2 encoded, >>1 works for supported values (1,2,4)
*/
+ if (pkt_per_line > 4)
+ drm_warn(msm_host->dev, "pkt_per_line too big");
reg |= DSI_VIDEO_COMPRESSION_MODE_CTRL_PKT_PER_LINE(pkt_per_line >> 1);
reg |= DSI_VIDEO_COMPRESSION_MODE_CTRL_EOL_BYTE_NUM(eol_byte_num);
reg |= DSI_VIDEO_COMPRESSION_MODE_CTRL_EN;

--
2.34.1