Haswell's DDI encoders have their own ->get_config callback and in
commit c6cd2ee2d59111a07cd9199564c9bdcb2d11e5cf
Author: Jani Nikula <jani.nikula@xxxxxxxxx>
Date: Mon Oct 21 10:52:07 2013 +0300
drm/i915/dp: workaround BIOS eDP bpp clamping issue
we've forgotten to replicate this hack. So let's do it that.
Note for backporters: The above commit and all it's depencies need to
be backported first.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71049
Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Gökçen Eraslan <gokcen.eraslan@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/i915/intel_ddi.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 1591576a6101..330077bcd0bd 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1406,6 +1406,26 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
default:
break;
}
+
+ if (encoder->type == INTEL_OUTPUT_EDP && dev_priv->vbt.edp_bpp &&
+ pipe_config->pipe_bpp > dev_priv->vbt.edp_bpp) {
+ /*
+ * This is a big fat ugly hack.
+ *
+ * Some machines in UEFI boot mode provide us a VBT that has 18
+ * bpp and 1.62 GHz link bandwidth for eDP, which for reasons
+ * unknown we fail to light up. Yet the same BIOS boots up with
+ * 24 bpp and 2.7 GHz link. Use the same bpp as the BIOS uses as
+ * max, not what it tells us to use.
+ *
+ * Note: This will still be broken if the eDP panel is not lit
+ * up by the BIOS, and thus we can't get the mode at module
+ * load.
+ */
+ DRM_DEBUG_KMS("pipe has %d bpp for eDP panel, overriding BIOS-provided max %d bpp\n",
+ pipe_config->pipe_bpp, dev_priv->vbt.edp_bpp);
+ dev_priv->vbt.edp_bpp = pipe_config->pipe_bpp;
+ }
}
static void intel_ddi_destroy(struct drm_encoder *encoder)
--
1.8.4.3
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