[Intel-gfx] [PATCH] drm/i915: read bpp from vbt only for older panels

[Sivakumar Thulasimani]

From: "Thulasimani,Sivakumar" <sivakumar.thulasimani at intel.com>

BPP bits defined in VBT should be used only on panels whose
edid version is 1.3 or older. EDID version 1.4 introduced offsets
where bpp is defined and read into display_info, hence bpp from
VBT will be used only when bpc in display_info is zero.

v2: use display_info.bpc for deciding when to use vbt_bpp (Jani)

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 44f8a32..ae00e86 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1409,7 +1409,10 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	 * bpc in between. */
 	bpp = pipe_config->pipe_bpp;
 	if (is_edp(intel_dp)) {
-		if (dev_priv->vbt.edp_bpp && dev_priv->vbt.edp_bpp < bpp) {
+
+		/* Get bpp from vbt only for panels that dont have bpp in edid */
+		if (intel_connector->base.display_info.bpc == 0 &&
+			(dev_priv->vbt.edp_bpp && dev_priv->vbt.edp_bpp < bpp)) {
 			DRM_DEBUG_KMS("clamping bpp for eDP panel to BIOS-provided %i\n",
 				      dev_priv->vbt.edp_bpp);
 			bpp = dev_priv->vbt.edp_bpp;
-- 
1.7.9.5