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drm/i915: Pick the first mode from EDID as the fixed mode when there is no preferred mode 

Some monitors apparently forget to mark any mode as preferred in the
EDID. In this particular case we have a very generic looking ID
"PNP Model 0 Serial Number 4" / "LVDS 800x600" so a specific quirk
doesn't seem particularly wise. Also the quirk we have
(EDID_QUIRK_FIRST_DETAILED_PREFERRED) is actually defunct so we'd
have to fix it first.

When there is no preferred mode we currently fall back to the VBT.
That approach fails us here as the VBT mode is 1024x768 whereas
the panel resolution is 800x600. So instead of falling back to the
VBT when there is no preferred mode let's just pick the first
probed mode. Only if the EDID provided no modes we fall back to
the VBT.

For this machine the VBIOS would appear to select the 800x600
60Hz EST mode rather than the first detailed mode (which is
the new fallback will pick). The two modes differ only by
having opposite sync polarities, which does not seem to matter
to the panel in question.

v2: Make sure the probed_modes list is not empty

Cc: Adam Jackson <ajax@redhat.com>
Cc: Roberto Viola <cagnulein@gmail.com>
Tested-by: Roberto Viola <cagnulein@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109780
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190321132446.22394-2-ville.syrjala@linux.intel.com
Reviewed-by: Adam Jackson <ajax@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Ville Syrjälä 2019-03-21 15:24:42 +02:00
parent 0dc927eb94
commit 8f49673ef9
1 changed files with 18 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpu/drm/i915/intel_panel.c
View File

@ -104,11 +104,13 @@ intel_panel_edid_fixed_mode(struct intel_connector *connector)
{
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
const struct drm_display_mode *scan;
struct drm_display_mode *fixed_mode;
if (list_empty(&connector->base.probed_modes))
return NULL;
/* prefer fixed mode from EDID if available */
list_for_each_entry(scan, &connector->base.probed_modes, head) {
struct drm_display_mode *fixed_mode;
if ((scan->type & DRM_MODE_TYPE_PREFERRED) == 0)
continue;
@ -123,7 +125,20 @@ intel_panel_edid_fixed_mode(struct intel_connector *connector)
return fixed_mode;
}
return NULL;
scan = list_first_entry(&connector->base.probed_modes,
typeof(*scan), head);
fixed_mode = drm_mode_duplicate(&dev_priv->drm, scan);
if (!fixed_mode)
return NULL;
fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] using first mode from EDID: ",
connector->base.base.id, connector->base.name);
drm_mode_debug_printmodeline(fixed_mode);
return fixed_mode;
}
/* adjusted_mode has been preset to be the panel's fixed mode */