In
commit 53d3b4d7778daf15900867336c85d3f8dd70600c
Author: Egbert Eich <eich@xxxxxxx>
Date: Tue Jun 4 17:13:21 2013 +0200
drm/i915/sdvo: Use &intel_sdvo->ddc instead of intel_sdvo->i2c for DDC
Ebgert 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).
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.
Cc: Egbert Eich <eich@xxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65524
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/i915/intel_sdvo.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 4c47b44..da3da8d 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1771,17 +1771,9 @@ static void intel_sdvo_get_lvds_modes(struct drm_connector *connector)
struct drm_i915_private *dev_priv = connector->dev->dev_private;
struct drm_display_mode *newmode;
- /*
- * Attempt to get the mode list from DDC.
- * Assume that the preferred modes are
- * 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 */
- if (dev_priv->sdvo_lvds_vbt_mode != NULL) {
+ /* Fetch modes from VBT. For SDVO prefer the VBT mode since some
+ * SDVO->LVDS transcoders can't cope with the EDID mode. */
+ if (dev_priv->vbt.sdvo_lvds_vbt_mode != NULL) {
newmode = drm_mode_duplicate(connector->dev,
dev_priv->sdvo_lvds_vbt_mode);
if (newmode != NULL) {
@@ -1789,9 +1781,18 @@ static void intel_sdvo_get_lvds_modes(struct drm_connector *connector)
newmode->type = (DRM_MODE_TYPE_PREFERRED |
DRM_MODE_TYPE_DRIVER);
drm_mode_probed_add(connector, newmode);
+
+ goto end;
}
}
+ /*
+ * Attempt to get the mode list from DDC.
+ * Assume that the preferred modes are
+ * arranged in priority order.
+ */
+ intel_ddc_get_modes(connector, &intel_sdvo->ddc);
+
end:
list_for_each_entry(newmode, &connector->probed_modes, head) {
if (newmode->type & DRM_MODE_TYPE_PREFERRED) {
--
1.7.10.4
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