[coreboot] question on libgfxinit DP port number

Nico Huber nico.h at gmx.de
Tue Jul 18 10:20:26 CEST 2017


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.



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