[REGRESSION] i915: No HDMI output with 4.4

[Oleksandr Natalenko]

16.02.2016 14:54, Daniel Vetter wrote:
>> Computer DVI ——— DVI-D (Single Link)/HDMI cable ——— HDMI LG 23MP65HQ-P 
>> ===
>> not working
> 
> I presume the above LG screen is what you've called previously "old
> monitor"?

Correct.

>> Computer DVI ——— DVI-D (Dual Link)/HDMI cable ——— HDMI LG 23MP65HQ-P 
>> ===
>> works!
> 
> Funky. Can you pls grab the debug logs (with the special patches from
> Ville) for this case? I wonder why suddenly different cable and it 
> works.

OK, but will have to steal it again, as it is the only dual link cable I 
could find on another workplace.

> Also: Is this one of these older-ish screens where you must have a
> dual-link cable to drive it at full resolution&refresh rate?
> -Daniel

Single-link cable is enough to empower LG 23MP65HQ-P as its standard 
resolution is 1920×1080 at 60, which is supported by single-link cable.

Dual-link cable comes with 27MP55HQ-P where it is required to provide 
higher resolution. BTW, in my previous email one should read 
"27MP55HQ-P" (not "23MP55HQ-P"). It is 27" monitor. Also, this monitor 
works with single-link cable (but at lower resolution, I guess).