[Intel-gfx] i915 4.9 regression: DP AUX CH sanitization no longer working on Asus desktops

[Ville Syrjälä]

On Thu, May 04, 2017 at 02:52:09PM -0600, Daniel Drake wrote:
> On Thu, May 4, 2017 at 2:37 PM, Ville Syrjälä
> <ville.syrjala at linux.intel.com> wrote:
> > Please check if commit bb1d132935c2 ("drm/i915/vbt: split out defaults
> > that are set when there is no VBT") fixes things for you.
> 
> I think this is not going to help. This would only make a difference
> when there is no VBT at all at which point we would see this message
> in the logs:
> 
>                 DRM_INFO("Failed to find VBIOS tables (VBT)\n");

No, the patch will in fact make a difference only when there is a VBT.

> 
> but in this case we have a VBT for ports B, C and E.
> 
>  [drm:intel_bios_init [i915]] Port B VBT info: DP:1 HDMI:1 DVI:1 EDP:0 CRT:0
>  [drm:intel_bios_init [i915]] VBT HDMI level shift for port B: 8
>  [drm:intel_bios_init [i915]] Port C VBT info: DP:0 HDMI:1 DVI:1 EDP:0 CRT:0
>  [drm:intel_bios_init [i915]] VBT HDMI level shift for port C: 8
>  [drm:intel_bios_init [i915]] Port E VBT info: DP:1 HDMI:0 DVI:0 EDP:0 CRT:0
>  [drm:intel_bios_init [i915]] VBT HDMI level shift for port E: 0
> 
> Let me know if I'm missing something and we will test it anyway

Please do.

-- 
Ville Syrjälä
Intel OTC