linux-kernel - [PATCH] drm/msm/dp: fix the max supported bpp logic

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Message-ID: <20240725220320.130916-1-quic_abhinavk@quicinc.com>
Date: Thu, 25 Jul 2024 15:03:19 -0700
From: Abhinav Kumar <quic_abhinavk@...cinc.com>
To: <freedreno@...ts.freedesktop.org>, Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov
	<dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten
	<marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, "Daniel
 Vetter" <daniel@...ll.ch>,
        Guenter Roeck <groeck@...omium.org>,
        Tanmay Shah
	<tanmay@...eaurora.org>,
        Vara Reddy <quic_varar@...cinc.com>,
        Stephen Boyd
	<swboyd@...omium.org>
CC: <dri-devel@...ts.freedesktop.org>, <quic_jesszhan@...cinc.com>,
        <neil.armstrong@...aro.org>, <abel.vesa@...aro.org>,
        <quic_khsieh@...cinc.com>, Rob Clark <robdclark@...omium.org>,
        "Chandan
 Uddaraju" <chandanu@...eaurora.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/msm/dp: fix the max supported bpp logic

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@...cinc.com>
---
 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);
+
 	drm_dbg_dp(panel->drm_dev, "updated bpp = %d\n",
 				dp_panel->dp_mode.bpp);
 
-- 
2.44.0