diff options
authorDaniel Vetter <>2013-06-10 09:47:58 +0200
committerDaniel Vetter <>2013-06-10 10:13:34 +0200
commitc3456fb3e4712d0448592af3c5d644c9472cd3c1 (patch)
parent7ba220cec0bbe9453c1f958cf282f84a157c924f (diff)
drm/i915: prefer VBT modes for SVDO-LVDS over EDIDdrm-intel-fixes-2013-06-11
In commit 53d3b4d7778daf15900867336c85d3f8dd70600c Author: Egbert Eich <> Date: Tue Jun 4 17:13:21 2013 +0200 drm/i915/sdvo: Use &intel_sdvo->ddc instead of intel_sdvo->i2c for DDC Egbert Eich fixed a long-standing bug where we simply used a non-working i2c controller to read the EDID for SDVO-LVDS panels. Unfortunately some machines seem to not be able to cope with the mode provided in the EDID. Specifically they seem to not be able to cope with a 4x pixel mutliplier instead of a 2x one, which seems to have been worked around by slightly changing the panels native mode in the VBT so that the dotclock is just barely above 50MHz. Since it took forever to notice the breakage it's fairly safe to assume that at least for SDVO-LVDS panels the VBT contains fairly sane data. So just switch around the order and use VBT modes first. v2: Also add EDID modes just in case, and spell Egbert correctly. v3: Elaborate a bit more about what's going on on Chris' machine. Cc: Egbert Eich <> Cc: Chris Wilson <> Bugzilla: Cc: Reported-and-tested-by: Chris Wilson <> Signed-off-by: Daniel Vetter <>
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index f44aa750332..d4ea6c265ce 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1777,10 +1777,13 @@ static void intel_sdvo_get_lvds_modes(struct drm_connector *connector)
* arranged in priority order.
intel_ddc_get_modes(connector, &intel_sdvo->ddc);
- if (list_empty(&connector->probed_modes) == false)
- goto end;
- /* Fetch modes from VBT */
+ /*
+ * Fetch modes from VBT. For SDVO prefer the VBT mode since some
+ * SDVO->LVDS transcoders can't cope with the EDID mode. Since
+ * drm_mode_probed_add adds the mode at the head of the list we add it
+ * last.
+ */
if (dev_priv->sdvo_lvds_vbt_mode != NULL) {
newmode = drm_mode_duplicate(connector->dev,
@@ -1792,7 +1795,6 @@ static void intel_sdvo_get_lvds_modes(struct drm_connector *connector)
list_for_each_entry(newmode, &connector->probed_modes, head) {
if (newmode->type & DRM_MODE_TYPE_PREFERRED) {
intel_sdvo->sdvo_lvds_fixed_mode =