@@ -1295,6 +1295,10 @@ struct edid_quirk {
* DP quirks in such cases.
*/
static const struct edid_quirk edid_quirk_list[] = {
+ /* Optional 4K AMOLED panel in the ThinkPad X1 Extreme 2nd Generation
+ * only supports DPCD backlight controls
+ */
+ { MFG(0x4c, 0x83), PROD_ID(0x41, 0x41), BIT(DP_QUIRK_FORCE_DPCD_BACKLIGHT) },
};
#undef MFG
@@ -328,15 +328,31 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
{
struct intel_panel *panel = &intel_connector->panel;
- struct drm_i915_private *dev_priv = to_i915(intel_connector->base.dev);
+ struct intel_dp *intel_dp = enc_to_intel_dp(intel_connector->encoder);
+ struct drm_device *dev = intel_connector->base.dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
if (i915_modparams.enable_dpcd_backlight == 0 ||
- (i915_modparams.enable_dpcd_backlight == -1 &&
- dev_priv->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE))
+ !intel_dp_aux_display_control_capable(intel_connector))
return -ENODEV;
- if (!intel_dp_aux_display_control_capable(intel_connector))
+ /*
+ * There are a lot of machines that don't advertise the backlight
+ * control interface to use properly in their VBIOS, :\
+ */
+ if (dev_priv->vbt.backlight.type !=
+ INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE &&
+ !drm_dp_has_quirk(&intel_dp->desc, intel_dp->edid_quirks,
+ DP_QUIRK_FORCE_DPCD_BACKLIGHT)) {
+ DRM_DEV_INFO(dev->dev,
+ "Panel advertises DPCD backlight support, but "
+ "VBT disagrees. If your backlight controls "
+ "don't work try booting with "
+ "i915.enable_dpcd_backlight=1. If your machine "
+ "needs this, please file a _new_ bug report on "
+ "drm/i915, see " FDO_BUG_URL " for details.\n");
return -ENODEV;
+ }
panel->backlight.setup = intel_dp_aux_setup_backlight;
panel->backlight.enable = intel_dp_aux_enable_backlight;
@@ -8,7 +8,6 @@
#include "i915_drv.h"
#include "i915_utils.h"
-#define FDO_BUG_URL "https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs"
#define FDO_BUG_MSG "Please file a bug on drm/i915; see " FDO_BUG_URL " for details."
void
@@ -34,6 +34,8 @@
struct drm_i915_private;
struct timer_list;
+#define FDO_BUG_URL "https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs"
+
#undef WARN_ON
/* Many gcc seem to no see through this and fall over :( */
#if 0
@@ -1538,6 +1538,16 @@ enum drm_dp_quirk {
* The DSC caps can be read from the physical aux instead.
*/
DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
+ /**
+ * @DP_QUIRK_FORCE_DPCD_BACKLIGHT:
+ *
+ * The device is telling the truth when it says that it uses DPCD
+ * backlight controls, even if the system's firmware disagrees. This
+ * quirk should be checked against both the ident and panel EDID.
+ * When present, the driver should honor the DPCD backlight
+ * capabilities advertised.
+ */
+ DP_QUIRK_FORCE_DPCD_BACKLIGHT,
};
/**