Regression: drm: Lobotomize set_busid nonsense for !pci drivers (a325725633c2)

[Laszlo Ersek]

Hello Daniel,

On 06/21/16 14:08, daniel.vetter at ffwll.ch (Daniel Vetter) wrote:
> We already have a fallback in place to fill out the unique from
> dev->unique, which is set to something reasonable in drm_dev_alloc.
> 
> Which means we only need to have a special set_busid for pci devices,
> to be able to care the backwards compat code for drm 1.1 around, which
> libdrm still needs.
> 
> While developing and testing this patch things blew up in really
> interesting ways, and the code is rather confusing in naming things
> between the kernel code, ioctl #defines and libdrm. For the next brave
> dragon slayer, document all this madness properly in the userspace
> interface section of gpu.tmpl.
> 
> v2: Make drm_dev_set_unique static and update kerneldoc.
> 
> v3: Entire rewrite, plus document what's going on for posterity in the
> gpu docbook uapi section.
> 
> v4: Drop accidental amdgpu hunk (Emil).
> 
> v5: Drop accidental omapdrm vblank counter change (Emil).
> 
> Cc: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> Cc: Emil Velikov <emil.l.velikov at gmail.com>
> Tested-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk> (virt_gpu)
> Reviewed-by: Emil Velikov <emil.l.velikov at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  Documentation/DocBook/gpu.tmpl                  |  4 ++
>  drivers/gpu/drm/armada/armada_drv.c             |  1 -
>  drivers/gpu/drm/drm_ioctl.c                     | 58 +++++++++++++++++++++++++
>  drivers/gpu/drm/drm_platform.c                  | 18 --------
>  drivers/gpu/drm/etnaviv/etnaviv_drv.c           |  1 -
>  drivers/gpu/drm/exynos/exynos_drm_drv.c         |  1 -
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c |  1 -
>  drivers/gpu/drm/imx/imx-drm-core.c              |  1 -
>  drivers/gpu/drm/msm/msm_drv.c                   |  1 -
>  drivers/gpu/drm/nouveau/nouveau_drm.c           |  1 -
>  drivers/gpu/drm/omapdrm/omap_drv.c              |  1 -
>  drivers/gpu/drm/shmobile/shmob_drm_drv.c        |  1 -
>  drivers/gpu/drm/tilcdc/tilcdc_drv.c             |  1 -
>  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 -
>  include/drm/drmP.h                              |  1 -
>  17 files changed, 62 insertions(+), 41 deletions(-)

This patch (commit a325725633c2) regresses X.org on QEMU's virtio-vga
device. Please see

  https://bugzilla.redhat.com/show_bug.cgi?id=1366842

complete with a bisection log under

  drivers/gpu/drm/virtio/

(comment 20).

Copying Thorsten so he can include this report in his next v4.8-rc8
regression report, if he chooses so. (Commit a325725633c2 is part of
v4.8-rc1, but we only managed to identify it now.) The last such report
I know of is archived e.g. at
<http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1239220.html>.

Reported-by: Joachim Frieben <jfrieben at hotmail.com>

Thanks
Laszlo