[arch-general] [RFC] Potentially deprecating primus, bumblebee, virtualGL and primus_vk

[Emil Velikov]

On Thu, 14 Jan 2021 at 18:15, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>
> On Wed, 13 Jan 2021 at 16:52, Archange <archange at archlinux.org> wrote:
> >
> > Le 12/01/2021 à 21:45, Emil Velikov a écrit :
> > > On Tue, 12 Jan 2021 at 18:24, Archange <archange at archlinux.org> wrote:
> > >
> > >> OK, will try to check tomorrow with a friend that has an Optimus laptop.
> > >>
> > > Perfect, thanks in advance.
> > >
> > > To trigger the event one has to echo into a sysfs file... Don't recall
> > > exactly, some of the following should be it.
> > > a) If the nvidia module is driving an fbcon:
> > >   - echo "0" > /sys/class/vtconsole/vtconX/bind
> > > b) and/or a combination of the following
> > >   - echo "remove" (or was it "unbind") > /sys/class/drm/cardX/device/uevent
> > >   - echo "remove" (or was it "unbind") >
> > > /sys/class/drm/cardX/device/driver/uevent
> > >   - echo "1" > /sys/class/drm/cardX/device/driver/unbind
> >
>
> > 2) If the driver is loaded before X, it works for PRIME. However, the
> > card refuse to unbind because it’s in use by X even if nothing is
> > actually running on it.
> >
> It just works here so I suspect that a command or the order was off.
>
> My setup:
> - Intel/Nvidia system, monitor plugged/powered by Intel GPU
> - Therefore fb0 is for Intel (alongside card0) and Nvidia does not
> have fb device only card1.
>
> What I've done:
> - Toggle render offload ON via xrandr, try glxgears
> - Toggle render offload OFF via xrandr
> - Issue the removal - echo "remove" > /sys/class/drm/card1/uevent
> - Confirm that it works - Xorg.0.log should list "removing GPU device
> ...blabla/card1"
> - No Nvidia fb - skipping the vtcon magic
> - Double-check nothing else is using the module - lsmod | grep
> nvidia_drm -> returns 0
> - Remove the nvidia module(s) - rmmod nvidia_drm (+ rest)
>
> In practise the above approach should work with reverse PRIME but
> honestly I haven't tried.
>
> Can you give it a try, step-by-step and let me know if any issues you
> encounter along the way.
>
Completely forgot: there is no need for an Optimus machine.
The above is applicable for any multi GPU setup - dual AMD, dual
Nvidia or any random 3+ combination.

The only hardcoded assumption of a) dual and b) optimus machine
seems** to be in BB.

-Emil
** From a quick read through the code a while ago.