Quoting Abhinav Kumar (2024-07-25 15:03:19)
> 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
> @@ -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);
Is the max_t() usage still required once 'max_supported_bpp' is also a
u32? Also, what is 18? Shouldn't that be some sort of define so we know
what it represents?
Or maybe none of that is required? From what I can tell,
dp_panel_get_mode_bpp() calls dp_panel_get_supported_bpp() which will
essentially clamp the bpp range between 18 and 30, unless
dp_panel->dp_mode.bpp is between 30 and 18 but not divisible by 6, e.g.
29. Perhaps this patch can be included and the max_t above dropped.
---8<--
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c
b/drivers/gpu/drm/msm/dp/dp_panel.c
index 07db8f37cd06..5cd7c138afd3 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -90,22 +90,22 @@ static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
static u32 dp_panel_get_supported_bpp(struct dp_panel *dp_panel,
u32 mode_edid_bpp, u32 mode_pclk_khz)
{
- struct dp_link_info *link_info;
+ const struct dp_link_info *link_info;
const u32 max_supported_bpp = 30, min_supported_bpp = 18;
- u32 bpp = 0, data_rate_khz = 0;
+ u32 bpp, data_rate_khz;
bpp = min_t(u32, mode_edid_bpp, max_supported_bpp);
link_info = &dp_panel->link_info;
data_rate_khz = link_info->num_lanes * link_info->rate * 8;
- while (bpp > min_supported_bpp) {
+ do {
if (mode_pclk_khz * bpp <= data_rate_khz)
- break;
+ return bpp;
bpp -= 6;
- }
+ } while (bpp > min_supported_bpp);
- return bpp;
+ return min_supported_bpp;
}
static int dp_panel_update_modes(struct drm_connector *connector,
