Bug#756522: bumblebee-nvidia: cannot access secondary gpu - error: Permission denied

[Vincent Cheng]

Hi Jean,

On Wed, Apr 29, 2015 at 5:06 AM, Jean Bernon Free <jbernon at free.fr> wrote:
>      I. On Wed, 29 Apr 2015 03:57:53 -0700 Vincent Cheng
>         <vcheng at debian.org> wrote:
>> Hi,
>>
>> On Wed, Apr 22, 2015 at 6:48 AM, JEBE <jbernon at free.fr> wrote:
>> > Package: bumblebee
>> > Version: 3.2.1-7
>> > Followup-For: Bug #756522
>> >
>> > Dear Maintainer,
>> >
>> > I installed bumblebee and primus packages, not bumblebee-nvidia. But I get the
>> > exact same issues and logs than described here.
>> [...]
>> > My bumblebee.conf has the line "driver= ". I understand that only
>> > "xorg.conf.nouveau" is active. Is that correct?
>>
>> Yes, if you only have either nvidia or nouveau installed, not both,
>> bumblebee will detect that (if you have both installed, bumblebee will
>> default to nvidia).
>>
>> [...]
>> > [  6143.889] (EE) [drm] KMS not enabled
>> > [  6143.889] (EE) No devices detected.
>>
>> Hmm...do you have nomodeset or nouveau.modeset=0 specified somewhere
>> (e.g. on your grub command line)? Is your GPU supported by nouveau?
>>
>> Regards,
>> Vincent
>>
>>
> Hi Vincent,
>
> Thanks for your attention.
>
> I have neither bumblebee-nvidia package or other nvidia driver
> installed.
>
> I had no nouveau.modeset option in grub. I tried to boot either with
> nouveau.modeset=1 option or with nouveau.nomodeset=0 option. It doesn't
> change anything in Xorg.8.log.
>
> Above the error you underlined, we found these lines in Xorg.8.log. They
> seem to show 1) that nouveau is loaded 2) that my GPU (Geforce 840M)
> should be supported. No ?

I'm actually not too sure about that. AFAIK the 840M is part of the
Maxwell family [1], and I don't actually know if the kernel/userspace
components are new enough in Debian to support Maxwell cards (your X
log suggests not?). You may have to do some googling to figure it out
for yourself.

Regards,
Vincent

[1] http://nouveau.freedesktop.org/wiki/CodeNames/