drm/nv50: ignore vbios table's claim to the contrary if EDID says >8bpc
Should fix dim panel issues reported on Dell M6400/M6500.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index a9263d9..90f0bf5 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -690,9 +690,21 @@
int pxclk)
{
struct drm_nouveau_private *dev_priv = dev->dev_private;
+ struct nouveau_connector *nv_connector = NULL;
+ struct drm_encoder *encoder;
struct nvbios *bios = &dev_priv->VBIOS;
uint32_t mc, script = 0, or;
+ list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+ struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
+
+ if (nv_encoder->dcb != dcbent)
+ continue;
+
+ nv_connector = nouveau_encoder_connector_get(nv_encoder);
+ break;
+ }
+
or = ffs(dcbent->or) - 1;
mc = nv50_display_mode_ctrl(dev, dcbent->type != OUTPUT_ANALOG, or);
switch (dcbent->type) {
@@ -711,6 +723,11 @@
} else
if (bios->fp.strapless_is_24bit & 1)
script |= 0x0200;
+
+ if (nv_connector && nv_connector->edid &&
+ (nv_connector->edid->revision >= 4) &&
+ (nv_connector->edid->input & 0x70) >= 0x20)
+ script |= 0x0200;
}
if (nouveau_uscript_lvds >= 0) {