Greg,
On 10/03/16 19:43, Laszlo Ersek wrote:
> Before commit a325725633c2 ("drm: Lobotomize set_busid nonsense for !pci
> drivers"), several DRM drivers for platform devices used to expose an
> explicit "drm_driver.set_busid" callback, invariably backed by
> drm_platform_set_busid().
>
> Commit a325725633c2 removed drm_platform_set_busid(), along with the
> referring .set_busid field initializations. This was justified because
> interchangeable functionality had been implemented in drm_dev_alloc() /
> drm_dev_init(), which DRM_IOCTL_SET_VERSION would rely on going forward.
>
> However, commit a325725633c2 also removed drm_virtio_set_busid(), for
> which the same consolidation was not appropriate: this .set_busid callback
> had been implemented with drm_pci_set_busid(), and not
> drm_platform_set_busid(). The error regressed Xorg/xserver on QEMU's
> "virtio-vga" card; the drmGetBusid() function from libdrm would no longer
> return stable PCI identifiers like "pci:0000:00:02.0", but rather unstable
> platform ones like "virtio0".
>
> Reinstate drm_virtio_set_busid() with judicious use of
>
> git checkout -p a325725633c2^ -- drivers/gpu/drm/virtio
>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxxx>
> Cc: Emil Velikov <emil.l.velikov@xxxxxxxxx>
> Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Joachim Frieben <jfrieben@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Joachim Frieben <jfrieben@xxxxxxxxxxx>
> Fixes: a325725633c26aa66ab940f762a6b0778edf76c0
> Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1366842
> Signed-off-by: Laszlo Ersek <lersek@xxxxxxxxxx>
> Reviewed-by: Emil Velikov <emil.l.velikov@xxxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_drm_bus.c | 10 ++++++++++
> drivers/gpu/drm/virtio/virtgpu_drv.c | 1 +
> drivers/gpu/drm/virtio/virtgpu_drv.h | 1 +
> 3 files changed, 12 insertions(+)
Is there any particular reason this patch hasn't been cherry-picked to
linux-4.8.y? (I checked v4.8.2.)
According to "Option 1" in "Documentation/stable_kernel_rules.txt", I
think it should have been.
Anyway, it is commit c2cbc38b9715bd8318062e600668fc30e5a3fbfa upstream;
please consider including it in v4.8.3.
(Daniel: my offer to test any further reworkings for this still stands;
just please send me patches that I can apply cleanly with git-am.)
Thanks!
Laszlo
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c
> index 7f0e93f87a55..88a39165edd5 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c
> @@ -27,6 +27,16 @@
>
> #include "virtgpu_drv.h"
>
> +int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master)
> +{
> + struct pci_dev *pdev = dev->pdev;
> +
> + if (pdev) {
> + return drm_pci_set_busid(dev, master);
> + }
> + return 0;
> +}
> +
> static void virtio_pci_kick_out_firmware_fb(struct pci_dev *pci_dev)
> {
> struct apertures_struct *ap;
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
> index c13f70cfc461..5820b7020ae5 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> @@ -117,6 +117,7 @@ static const struct file_operations virtio_gpu_driver_fops = {
>
> static struct drm_driver driver = {
> .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_RENDER | DRIVER_ATOMIC,
> + .set_busid = drm_virtio_set_busid,
> .load = virtio_gpu_driver_load,
> .unload = virtio_gpu_driver_unload,
> .open = virtio_gpu_driver_open,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index b18ef3111f0c..acf556a35cb2 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -49,6 +49,7 @@
> #define DRIVER_PATCHLEVEL 1
>
> /* virtgpu_drm_bus.c */
> +int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master);
> int drm_virtio_init(struct drm_driver *driver, struct virtio_device *vdev);
>
> struct virtio_gpu_object {
>
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