[coreboot] question on libgfxinit DP port number

[Iru Cai]

Thanks, Nico


On 2017年07月18日 16:20, Nico Huber wrote:
> Hi Iru,
>
> On 18.07.2017 09:28, Iru Cai wrote:
>> Hi,
>>
>> I found the mainboard DP port doesn't have output before kernel starts in
>> hp/2570p (https://review.coreboot.org/c/20489/). After I added DP3 and
>> HDMI3 in port list, the DP port had output, and cbmem log said it's DP3.
>> However, xrandr says this port is DP2. What is the problem?
> libgfxinit only knows about physical ports (i.e. how they are ordered*
> in the datasheet). Linux ignores ports that aren't strapped to be active
> (or are disabled by VBT) and renumbers the ports to fill the holes.
>
> Nico
>
> * The numbering is not perfect. As historically VGA was the first port
>   (port A in datasheets), digital ports are counted from B, so DP1 is
>   port B, DP2 is port C, etc.

Now I found /sys/class/drm_dp_aux_dev/drm_dp_aux{0,1} (Linux 4.4) and
`cat /sys/class/drm_dp_aux_dev/*/name` gives me:
  DPDDC-B
  DPDDC-D

So should the ports be DP1 and DP3?

Iru