Re: xsrc/55743: There is no support for VGA arbiter thus no multi PCI card support (with possible fix)

[Michael <macallan%netbsd.org@localhost>]

The following reply was made to PR xsrc/55743; it has been noted by GNATS.

From: Michael <macallan%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: xsrc/55743: There is no support for VGA arbiter thus no multi
 PCI card support (with possible fix)
Date: Thu, 22 Oct 2020 13:05:37 -0400

 Hello,
 
 > [ 13277.638] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
 > 
 > And thus all other cards seem to be ignored. The /dev/dri/card0 and
 > /dev/dri/card1 devices are opened multiple times and queried and the
 > enumeration in X also goes well so I think it bombs out on this.
 > 
 > 	
 > >How-To-Repeat:  
 > 	
 > Plug two PCI (or PCI-e or whatever) graphic cards in one machine and start X.
 
 IIRC this is for the fixed VGA IO registers only, which would overlap.
 I have used multiple PCI VGAs on non-x86 hardware ( which tends to
 leave those disabled and just use the BARs ) since ~forever, without
 the arbiter.
 I seriously doubt that there's a lot graphics hardware made in this
 century which depends on the fixed VGA registers, or even has them
 enabled on powerup.
 
 We should probably drop the arbiter requirement and just let X
 configure whatever it finds.
 
 have fun
 Michael