Commit 294b3810 authored by Jonathan Marek's avatar Jonathan Marek Committed by Dmitry Baryshkov
Browse files

drm/msm/dsi: add a comment to explain pkt_per_line encoding 



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

Signed-off-by: default avatarJonathan Marek <jonathan@marek.ca>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: default avatarJun Nie <jun.nie@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK
Reviewed-by: default avatarJessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/596236/
Link: https://lore.kernel.org/r/20240530-msm-drm-dsc-dsi-video-upstream-4-v6-6-2ab1d334c657@linaro.org


Signed-off-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
parent 9ecd0ddd

drivers/gpu/drm/msm/dsi/dsi_host.c

+4 −0
Original line number Diff line number Diff line
@@ -885,7 +885,11 @@ 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_once(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;