[Intel-gfx] [PATCH 1/3] RFC: drm: Restrict vblank ioctl to master

[Rainer Hochecker]

Hi Daniel,

We are in beta for v18. I expect release in September.
I don't think we have to consider users who run older Kodi versions on
systems with latest kernels. The feature the patch would disable won't
make Kodi completely unusable when absent. I'd say you can merge
the patch short after v18 has been released.

Cheers,
Rainer

On Wed, Aug 8, 2018 at 6:59 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> Hi Rainer,
>
> Awesome, thanks a lot for doing this! Any idea for when this will ship
> in a release, and for how long your users are generally using older
> releases? Just to have a rough indication for when we could attempt to
> merge this patch here.
>
> Cheers, Daniel
>
> On Wed, Aug 8, 2018 at 5:35 PM, Rainer Hochecker <fernetmenta at kodi.tv> wrote:
>> Finally we removed this code from Kodi.
>>
>> Regards,
>> Rainer
>>
>> On Tue, Jun 14, 2016 at 11:02 AM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
>>> Somehow this escaped us, this is a KMS ioctl which should only be used
>>> by the master (which is the thing that's also in control of kms
>>> resources). Everything else is bound to result in fail.
>>>
>>> Clients shouldn't have a trouble coping with this, since a pile of
>>> drivers don't support vblank waits (or just randomly fall over when
>>> using them). Note that the big motivation for abusing this like mad
>>> seems to be that EGL doesn't have OML_sync, but somehow it didn't
>>> cross anyone's mind that adding OML_sync to EGL would be useful. This
>>> patch is meant to essentially start kicking that can from the back
>>> end.
>>>
>>> Cc: fritsch at kodi.tv
>>> Cc: fernetmenta at kodi.tv
>>> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
>>> ---
>>>  drivers/gpu/drm/drm_ioctl.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>>> index 0510675eec5d..6cc78d648393 100644
>>> --- a/drivers/gpu/drm/drm_ioctl.c
>>> +++ b/drivers/gpu/drm/drm_ioctl.c
>>> @@ -529,9 +529,9 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
>>>         DRM_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_legacy_sg_alloc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
>>>         DRM_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_legacy_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
>>>
>>> -       DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank, DRM_UNLOCKED),
>>> +       DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank, DRM_MASTER|DRM_UNLOCKED),
>>>
>>> -       DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_modeset_ctl, 0),
>>> +       DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_modeset_ctl, DRM_MASTER),
>>>
>>>         DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
>>>
>>> --
>>> 2.8.1
>>>
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch