[Regression] Hdmi display broken on skylake (detected but blank or glitching)
- CPU: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
- GPU: Intel Corporation HD Graphics 530
- Laptop model: Asus ROG GL552VW
Following up on this issue #835 (closed), I finally managed to bisect the kernel and found out that this patch (0519c102f5285476d7868a387bdb6c58385e4074) breaks hdmi display on my laptop (I can still use an external screen at low resolution / frequencies but the screen keeps handshaking anyway).
Building latest drm-tip with this trivial patch solves the problem:
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 73d0f4648c06..17123a49ac03 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3570,7 +3570,7 @@ static void intel_enable_ddi_hdmi(struct intel_encoder *encoder,
connector->base.id, connector->name);
/* Display WA #1143: skl,kbl,cfl */
- if (IS_GEN9_BC(dev_priv)) {
+ if (false && IS_GEN9_BC(dev_priv)) {
/*
* For some reason these chicken bits have been
* stuffed into a transcoder register, event though