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From: <gregkh@linuxfoundation.org>
To: jani.nikula@intel.com, shawn.c.lee@intel.com,
	stable@vger.kernel.org, ville.syrjala@linux.intel.com
Cc: <stable@vger.kernel.org>
Subject: FAILED: patch "[PATCH] drm/edid: fix CEA extension byte #3 parsing" failed to apply to 5.16-stable tree
Date: Sat, 02 Apr 2022 14:29:38 +0200	[thread overview]
Message-ID: <16489025781813@kroah.com> (raw)


The patch below does not apply to the 5.16-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.

For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.

Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable@vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani.nikula@intel.com

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
 
 	/* The existence of a CEA block should imply RGB support */
 	info->color_formats = DRM_COLOR_FORMAT_RGB444;
-	if (edid_ext[3] & EDID_CEA_YCRCB444)
-		info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
-	if (edid_ext[3] & EDID_CEA_YCRCB422)
-		info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+	/* CTA DisplayID Data Block does not have byte #3 */
+	if (edid_ext[0] == CEA_EXT) {
+		if (edid_ext[3] & EDID_CEA_YCRCB444)
+			info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+		if (edid_ext[3] & EDID_CEA_YCRCB422)
+			info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+	}
 
 	if (cea_db_offsets(edid_ext, &start, &end))
 		return;


                 reply	other threads:[~2022-04-02 12:29 UTC|newest]

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