On Sunday, May 24, 2020 8:53 PM, Daniel Vetter <daniel@xxxxxxxx> wrote: > On Sat, May 23, 2020 at 5:44 PM Mauro Rossi issor.oruam@xxxxxxxxx wrote: > > > OpenByFB is introduced to overcome GPU driver loading order issue > > on a device with multiple GPUs, e.g. Intel iGPU and Nvidia dGPU > > where the first drmfb kernel module loaded will become device file > > /dev/dri/card0 and the second will become /dev/dri/card1 > > The use case is to prefer Intel iGPU over dGPU, or viceversa, > > in a deterministic and reliable manner. > > OpenByFB function opens the DRM device with specified fb and node type, > > thus enabling gralloc to open the correct device node of the primary fb, > > regardless of the GPU driver loading order. > > The fbdev load ordering is as inconsistent/random as the dri node > loading. Well more so, because you might have random firmware fbdev > drivers hanging out there. Hence I'm not following how this solves > anything for your problem. > > I think usually what userspace does it look at the boot_vga property > of the underlying device in sysfs, and prefer that one. Yes. See [1] for an example of how to do this. [1]: https://github.com/swaywm/wlroots/blob/5c942bd5972afee9a68cb15c14aa83b4b0aaf82d/backend/session/session.c#L331 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
