drm/edid: fix AVI infoframe aspect ratio handling

We try to avoid sending VICs defined in the later specs in AVI
infoframes to sinks that conform to the earlier specs, to not upset
them, and use 0 for the VIC instead. However, we do this detection and
conversion to 0 too early, as we'll need the actual VIC to figure out
the aspect ratio.

In particular, for a mode with 64:27 aspect ratio, 0 for VIC fails the
AVI infoframe generation altogether with -EINVAL.

Separate the VIC lookup from the "filtering", and postpone the
filtering, to use the proper VIC for aspect ratio handling, and the 0
VIC for the infoframe video code as needed.

Reported-by: William Tseng <william.tseng@intel.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6153
References: https://lore.kernel.org/r/20220920062316.43162-1-william.tseng@intel.com
Cc: <stable@vger.kernel.org>
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/c3e78cc6d01ed237f71ad0038826b08d83d75eef.1672826282.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3841aba17abdc666632370b204370e7913bbef22..23f7146e6a9b46c600a17e9f0aaaa4eb3bdb02e7 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6885,8 +6885,6 @@ static u8 drm_mode_hdmi_vic(const struct drm_connector *connector,
 static u8 drm_mode_cea_vic(const struct drm_connector *connector,
                           const struct drm_display_mode *mode)
 {
-       u8 vic;
-
        /*
         * HDMI spec says if a mode is found in HDMI 1.4b 4K modes
         * we should send its VIC in vendor infoframes, else send the
@@ -6896,13 +6894,18 @@ static u8 drm_mode_cea_vic(const struct drm_connector *connector,
        if (drm_mode_hdmi_vic(connector, mode))
                return 0;
 
-       vic = drm_match_cea_mode(mode);
+       return drm_match_cea_mode(mode);
+}
 
-       /*
-        * HDMI 1.4 VIC range: 1 <= VIC <= 64 (CEA-861-D) but
-        * HDMI 2.0 VIC range: 1 <= VIC <= 107 (CEA-861-F). So we
-        * have to make sure we dont break HDMI 1.4 sinks.
-        */
+/*
+ * Avoid sending VICs defined in HDMI 2.0 in AVI infoframes to sinks that
+ * conform to HDMI 1.4.
+ *
+ * HDMI 1.4 (CTA-861-D) VIC range: [1..64]
+ * HDMI 2.0 (CTA-861-F) VIC range: [1..107]
+ */
+static u8 vic_for_avi_infoframe(const struct drm_connector *connector, u8 vic)
+{
        if (!is_hdmi2_sink(connector) && vic > 64)
                return 0;
 
@@ -6978,7 +6981,7 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
                picture_aspect = HDMI_PICTURE_ASPECT_NONE;
        }
 
-       frame->video_code = vic;
+       frame->video_code = vic_for_avi_infoframe(connector, vic);
        frame->picture_aspect = picture_aspect;
        frame->active_aspect = HDMI_ACTIVE_ASPECT_PICTURE;
        frame->scan_mode = HDMI_SCAN_MODE_UNDERSCAN;