On 7/27/2024 5:51 AM, Dmitry Baryshkov wrote:
On Fri, 26 Jul 2024 at 01:04, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:Currently the DP driver hard-codes the max supported bpp to 30. This is incorrect because the number of lanes and max data rate supported by the lanes need to be taken into account. Replace the hardcoded limit with the appropriate math which accounts for the accurate number of lanes and max data rate. Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> --- drivers/gpu/drm/msm/dp/dp_panel.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c index a916b5f3b317..56ce5e4008f8 100644 --- a/drivers/gpu/drm/msm/dp/dp_panel.c +++ b/drivers/gpu/drm/msm/dp/dp_panel.c @@ -397,6 +397,7 @@ int dp_panel_init_panel_info(struct dp_panel *dp_panel) { struct drm_display_mode *drm_mode; struct dp_panel_private *panel; + u32 max_supported_bpp; drm_mode = &dp_panel->dp_mode.drm_mode; @@ -423,8 +424,10 @@ int dp_panel_init_panel_info(struct dp_panel *dp_panel) drm_mode->clock); drm_dbg_dp(panel->drm_dev, "bpp = %d\n", dp_panel->dp_mode.bpp); - dp_panel->dp_mode.bpp = max_t(u32, 18, - min_t(u32, dp_panel->dp_mode.bpp, 30)); + max_supported_bpp = dp_panel_get_mode_bpp(dp_panel, dp_panel->dp_mode.bpp, + dp_panel->dp_mode.drm_mode.clock); + dp_panel->dp_mode.bpp = max_t(u32, 18, max_supported_bpp);I think that in mode_valid() the driver should filter out modes that result in BPP being less than 18. Then the max_t can be dropped completely.
With Stephen's suggested change, dp_panel_get_supported_bpp() will not return anything below min_supported_bpp which is 18 so we can absorb that part and drop the max_t part here.
Nevertheless this indeed fixes an issue with the screen corruption, this is great! Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> # SM8350-HDK
Thanks for reporting and testing this. I need to give you Reported-by credits as well.
+ drm_dbg_dp(panel->drm_dev, "updated bpp = %d\n", dp_panel->dp_mode.bpp); -- 2.44.0
