linux-kernel - [PATCH] drm/amd/display: do not copy invalid CRTC timing info

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Message-ID: <24439c13a014e1cd200785db6f3dcf08f4773eb3.1743612701.git.soyer@irl.hu>
Date: Wed,  2 Apr 2025 19:03:31 +0200
From: Gergo Koteles <soyer@....hu>
To: Harry Wentland <harry.wentland@....com>,
  Leo Li <sunpeng.li@....com>, Rodrigo Siqueira <siqueira@...lia.com>,
  Alex Deucher <alexander.deucher@....com>,
  Christian König <christian.koenig@....com>,
  David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
  Alex Hung <alex.hung@....com>,
  Mario Limonciello <mario.limonciello@....com>,
  Tom Chung <chiahsuan.chung@....com>,
  Sunil Khatri <sunil.khatri@....com>,
  Aurabindo Pillai <aurabindo.pillai@....com>,
  Hersen Wu <hersenxs.wu@....com>, Melissa Wen <mwen@...lia.com>,
  Maxime Ripard <mripard@...nel.org>,
  Dmitry Baryshkov <lumag@...nel.org>,
  Thomas Zimmermann <tzimmermann@...e.de>,
  Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
Cc: amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
  linux-kernel@...r.kernel.org, regressions@...ts.linux.dev,
  Gergo Koteles <soyer@....hu>
Subject: [PATCH] drm/amd/display: do not copy invalid CRTC timing info

Since b255ce4388e0, it is possible that the CRTC timing
information for the preferred mode has not yet been
calculated while amdgpu_dm_connector_mode_valid() is running.

In this case use the CRTC timing information of the actual mode.

Fixes: b255ce4388e0 ("drm/amdgpu: don't change mode in amdgpu_dm_connector_mode_valid()")
Closes: https://lore.kernel.org/all/ed09edb167e74167a694f4854102a3de6d2f1433.camel@irl.hu/
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4085
Signed-off-by: Gergo Koteles <soyer@....hu>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index bae83a129b5f..0eb25cdcb52f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6500,12 +6500,12 @@ decide_crtc_timing_for_drm_display_mode(struct drm_display_mode *drm_mode,
 					const struct drm_display_mode *native_mode,
 					bool scale_enabled)
 {
-	if (scale_enabled) {
-		copy_crtc_timing_for_drm_display_mode(native_mode, drm_mode);
-	} else if (native_mode->clock == drm_mode->clock &&
-			native_mode->htotal == drm_mode->htotal &&
-			native_mode->vtotal == drm_mode->vtotal) {
-		copy_crtc_timing_for_drm_display_mode(native_mode, drm_mode);
+	if (scale_enabled || (
+	    native_mode->clock == drm_mode->clock &&
+	    native_mode->htotal == drm_mode->htotal &&
+	    native_mode->vtotal == drm_mode->vtotal)) {
+		if (native_mode->crtc_clock)
+			copy_crtc_timing_for_drm_display_mode(native_mode, drm_mode);
 	} else {
 		/* no scaling nor amdgpu inserted, no need to patch */
 	}
-- 
2.49.0