Re: Blank console but X11 works on MCP79 - old regression since 3.8

From: Ilia Mirkin
Date: Fri Nov 17 2017 - 09:43:44 EST

With a new kernel, mind grabbing a dmesg with drm.debug=0x1e
nouveau.debug=debug (or maybe even =trace)? Maybe also see if
fbcon/fbdev have any debug things that can be turned on?

Sounds like things are generally working, just the fbcon -> nouveaufb
path seems somehow buggered.

Another thing to try would be nouveau.atomic=1

On Fri, Nov 17, 2017 at 9:26 AM, Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
> I've just been hit by this old bug which is still present in 4.14:
> On MCP79 (ION), when stolen memory is set to 32MB in BIOS, console is blank
> but X11 works. When the stolen memory is increased to 64MB, console works
> fine.
> Bisected it to this:
> 4f6029da58ba9204c98e33f4f3737fe085c87a6f is the first bad commit
> commit 4f6029da58ba9204c98e33f4f3737fe085c87a6f
> Author: Ben Skeggs <bskeggs@xxxxxxxxxx>
> Date: Fri Nov 16 11:54:31 2012 +1000
> drm/nv50-nvc0: switch to common disp impl, removing previous version
> Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
> It's a big change so I'm not able to do more debugging.
> --
> Ondrej Zary