drm/edid: Introduce is_detailed_timing_descritor()

Let's introduce is_detailed_timing_descritor() as the opposite
counterpart of is_display_descriptor().

Cc: Allen Chen <allen.chen@ite.com.tw>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200124200231.10517-3-ville.syrjala@linux.intel.com
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index e878b0c839a0b9cc278548e4a2a1bac9a846f0b7..c0d4635c07d5ce32604761a2492121d0e71ae661 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2218,6 +2218,11 @@ static bool is_display_descriptor(const u8 d[18], u8 tag)
                d[2] == 0x00 && d[3] == tag;
 }
 
+static bool is_detailed_timing_descriptor(const u8 d[18])
+{
+       return d[0] != 0x00 || d[1] != 0x00;
+}
+
 typedef void detailed_cb(struct detailed_timing *timing, void *closure);
 
 static void
@@ -3117,27 +3122,28 @@ do_detailed_mode(struct detailed_timing *timing, void *c)
        struct detailed_mode_closure *closure = c;
        struct drm_display_mode *newmode;
 
-       if (timing->pixel_clock) {
-               newmode = drm_mode_detailed(closure->connector->dev,
-                                           closure->edid, timing,
-                                           closure->quirks);
-               if (!newmode)
-                       return;
+       if (!is_detailed_timing_descriptor((const u8 *)timing))
+               return;
+
+       newmode = drm_mode_detailed(closure->connector->dev,
+                                   closure->edid, timing,
+                                   closure->quirks);
+       if (!newmode)
+               return;
 
-               if (closure->preferred)
-                       newmode->type |= DRM_MODE_TYPE_PREFERRED;
+       if (closure->preferred)
+               newmode->type |= DRM_MODE_TYPE_PREFERRED;
 
-               /*
-                * Detailed modes are limited to 10kHz pixel clock resolution,
-                * so fix up anything that looks like CEA/HDMI mode, but the clock
-                * is just slightly off.
-                */
-               fixup_detailed_cea_mode_clock(newmode);
+       /*
+        * Detailed modes are limited to 10kHz pixel clock resolution,
+        * so fix up anything that looks like CEA/HDMI mode, but the clock
+        * is just slightly off.
+        */
+       fixup_detailed_cea_mode_clock(newmode);
 
-               drm_mode_probed_add(closure->connector, newmode);
-               closure->modes++;
-               closure->preferred = false;
-       }
+       drm_mode_probed_add(closure->connector, newmode);
+       closure->modes++;
+       closure->preferred = false;
 }
 
 /*