Hi Christian, On Sun, Nov 19, 2023 at 5:28 PM Christian Zigotzky <chzigotzky@xxxxxxxxxxx> wrote: > On 16 November 2023 at 03:44 pm, Gerd Hoffmann wrote: > > On Thu, Nov 16, 2023 at 02:16:54PM +0100, Geert Uytterhoeven wrote: > >> When using virtgpu on a big-endian machine, e.g. powerpc QEMU: > >> > >> virtio-pci 0000:00:02.0: [drm] *ERROR* fbdev: Failed to setup generic emulation (ret=-2) > >> > >> or m68k/virt: > >> > >> virtio-mmio virtio-mmio.125: [drm] *ERROR* fbdev: Failed to setup generic emulation (ret=-2) > >> > >> and the graphical display fails to come up. > >> > >> Before, the call to drm_mode_addfb() caused a translation from a fourcc > >> format (XR24) to a bpp/depth pair (32/24) to a potentially different fourcc > >> format (BX24 on big-endian), due to the quirk processing in > >> drm_driver_legacy_fb_format(). After, the original fourcc format (XR24) > >> is passed unmodified. > >> > >> However, the virtgpu DRM driver supports only a single format for its > >> main plane: DRM_FORMAT_HOST_XRGB8888, which is XR24 on little-endian, > >> and BX24 on big-endian. I.e. on big-endian, virtgpu does not support > >> XR24, which is the default DRM format, and must be supported by all > >> drivers. Before, this was reported, but didn't lead to a failure: > >> > >> virtio-mmio virtio-mmio.125: [drm] bpp/depth value of 32/24 not supported > >> virtio-mmio virtio-mmio.125: [drm] No compatible format found > >> > >> As the core virtgpu driver and device support both XR24 and BX24 on both > >> little-endian and big-endian just fine, fix this extending the list of > >> supported formats for main plane and cursor plane to XR24/BX24 resp. > >> AR24/BA24. > >> > >> Fixes: 6ae2ff23aa43a0c4 ("drm/client: Convert drm_client_buffer_addfb() to drm_mode_addfb2()") > >> Reported-by: Christian Zigotzky <chzigotzky@xxxxxxxxxxx> > >> Closes: https://lore.kernel.org/r/c47fba21-3ae9-4021-9f4a-09c2670ebdbc@xxxxxxxxxxx > >> Suggested-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> > >> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > > Reviewed-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> > > The new patch works but I don't see the virtio-mouse-pci pointer > anymore. I see the pointer with -device usb-tablet. Please check the > second patch. I will use the first patch for the RC2 of kernel 6.7. That's probably partially explained by commit 99748ab64fcc8578 ("drm: virtio: fix virtio_gpu_cursor_formats"), which forced BA24 for the cursor plane on big-endian, but unfortunately linked thread doesn't contain the full picture. Where is the default cursor format defined? I see virtio_gpu_mode_dumb_create() still defaults to DRM_FORMAT_HOST_XRGB8888. However, that can't be the cause, as the cursor formats require an alpha channel. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds