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| author | Pengyu Luo <mitltlatltl@gmail.com> | 2026-02-14 13:51:28 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-03-25 13:08:26 +0300 |
| commit | 275dc9f8bc3c19b2acd1b357d3b328d24d1cb5d6 (patch) | |
| tree | cae0cbd9010b8293f7221bc0df54092fa2a9cd46 /drivers | |
| parent | 7e2963773760a664684435201960dd2fb712f1b5 (diff) | |
| download | linux-275dc9f8bc3c19b2acd1b357d3b328d24d1cb5d6.tar.xz | |
drm/msm/dsi: fix hdisplay calculation when programming dsi registers
[ Upstream commit ac47870fd795549f03d57e0879fc730c79119f4b ]
Recently, the hdisplay calculation is working for 3:1 compressed ratio
only. If we have a video panel with DSC BPP = 8, and BPC = 10, we still
use the default bits_per_pclk = 24, then we get the wrong hdisplay. We
can draw the conclusion by cross-comparing the calculation with the
calculation in dsi_adjust_pclk_for_compression().
Since CMD mode does not use this, we can remove
!(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO) safely.
Fixes: efcbd6f9cdeb ("drm/msm/dsi: Enable widebus for DSI")
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/704822/
Link: https://lore.kernel.org/r/20260214105145.105308-1-mitltlatltl@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/msm/dsi/dsi_host.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index d22e01751f5e..c85d0d5fc580 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -944,7 +944,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi) if (msm_host->dsc) { struct drm_dsc_config *dsc = msm_host->dsc; - u32 bytes_per_pclk; + u32 bits_per_pclk; /* update dsc params with timing params */ if (!dsc || !mode->hdisplay || !mode->vdisplay) { @@ -966,7 +966,9 @@ 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, bus width is extended to 6 bytes. + * 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. * * Calculate the number of pclks needed to transmit one line of * the compressed data. @@ -978,12 +980,12 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi) * unused anyway. */ h_total -= hdisplay; - if (wide_bus_enabled && !(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO)) - bytes_per_pclk = 6; + if (wide_bus_enabled) + bits_per_pclk = mipi_dsi_pixel_format_to_bpp(msm_host->format); else - bytes_per_pclk = 3; + bits_per_pclk = 24; - hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc), bytes_per_pclk); + hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc) * 8, bits_per_pclk); h_total += hdisplay; ha_end = ha_start + hdisplay; |