[Nouveau] [INVALID_ARG] mthd 0414

[Karol Herbst]

On Fri, Nov 19, 2021 at 2:00 PM dmanye <dmanye at urv.cat> wrote:
>
> On 19/11/21 13:31, Karol Herbst wrote:
> > yeah.. not quite sure yet. I tried it out with my gk208b gpus, but
> > couldn't hit anything. Maybe using VGA makes the difference here. Or
> > something else is different. Might also already be fixed in 5.16...
> > too many unknowns still. I will do another round of testing with VGA
> > and see how that ends.
>
> hello again,
>
> thanks for your effort Karol. i've just found another time the bug and:
>
> 1) kept the vga cable in the same place.
>
> 2) connected a dvi cable between the same computer and the same monitor.
>
> 3) told xrandr to dup the signal through the dvi cable:
>
> DISPLAY=:0.0 xrandr --output DVI-D-1 --mode "1920x1080" --same-as VGA-1
>
> 4) voilà! the monitor, all alone, switched to dvi input and there is my
> x session up and running.
>
> 5) if i force the monitor to change to vga input it refuses it and
> returns to dvi
>
> so i think the driver does its job but without actually sending anything
> through the vga cable.
>

yeah.. not quite sure yet what's going on here. Maybe the cable are
just a bit broken, or.... other signals interfering or whatever. Maybe
a driver bug. VGA being an analog signal and stuff makes it a bit
painful to tell what's wrong. If dmesg is clean, then no idea how to
dig into this even. I couldn't reproduce it with my Fedora system
running the latest 5.10 kernel either with VGA.

Could also be the displays being weird...

Anyway, if using DVI is an option for you I highly recommend using
that. But I'd also like to figure out what's wrong here.

What I think could help is to enable drm debugging once you hit the
error. For that you can write "0x1ff" into
/sys/module/drm/paramters/debug as root, restart X, change the
resolution via xrandr to force X to set a new mode on the connector
and pastebin the output of dmesg somewhere. Maybe that helps, maybe
not. Let's see what information that gives us.

>
> thanks.
>
>