[PATCH 09/14] drm: Remove the legacy DRM_IOCTL_MODESET_CTL ioctl

[Alex Deucher]

On Wed, Nov 22, 2023 at 7:25 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>
> DRM drivers with user-space mode setting have been removed in Linux
> v6.3. [1] Now remove the ioctl entry points for these drivers. Invoking
> any of the ioctl ops will unconditionally return -EINVAL to user space.
>
> Invoking DRM_IOCTL_MODESET_CTL is different from the other legacy
> ioctl ops as it returns 0 even without CONFIG_DRM_LEGACY set. From the
> original commit 29935554b384 ("drm: Disallow DRM_IOCTL_MODESET_CTL for
> KMS drivers") it is not apparent how or why the operation differs from
> the others. It is likely just an oversight in commit 61ae227032e7
> ("drm: allow removal of legacy codepaths (v4.1)"), which allowed
> disabling leagacy ioctls in the first place. Still keep this removal
> separate from the other ioctls to allow an easy revert, if necessary.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Link: https://patchwork.freedesktop.org/series/111602/ # [1]

Acked-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/drm_internal.h |  2 -
>  drivers/gpu/drm/drm_ioctl.c    |  2 -
>  drivers/gpu/drm/drm_vblank.c   | 82 ----------------------------------
>  3 files changed, 86 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
> index b12c463bc4605..a538a48c7d952 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -117,8 +117,6 @@ void drm_handle_vblank_works(struct drm_vblank_crtc *vblank);
>  /* IOCTLS */
>  int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
>                           struct drm_file *filp);
> -int drm_legacy_modeset_ctl_ioctl(struct drm_device *dev, void *data,
> -                                struct drm_file *file_priv);
>
>  /* drm_irq.c */
>
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index e6c32f76c7452..9c6326b908e74 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -585,8 +585,6 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
>
>         DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank_ioctl, DRM_UNLOCKED),
>
> -       DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_legacy_modeset_ctl_ioctl, 0),
> -
>         DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
>
>         DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_RENDER_ALLOW),
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index 877e2067534fa..a11f164b2384f 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -1574,88 +1574,6 @@ void drm_crtc_vblank_restore(struct drm_crtc *crtc)
>  }
>  EXPORT_SYMBOL(drm_crtc_vblank_restore);
>
> -static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
> -                                         unsigned int pipe)
> -{
> -       struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -       /* vblank is not initialized (IRQ not installed ?), or has been freed */
> -       if (!drm_dev_has_vblank(dev))
> -               return;
> -
> -       if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
> -               return;
> -
> -       /*
> -        * To avoid all the problems that might happen if interrupts
> -        * were enabled/disabled around or between these calls, we just
> -        * have the kernel take a reference on the CRTC (just once though
> -        * to avoid corrupting the count if multiple, mismatch calls occur),
> -        * so that interrupts remain enabled in the interim.
> -        */
> -       if (!vblank->inmodeset) {
> -               vblank->inmodeset = 0x1;
> -               if (drm_vblank_get(dev, pipe) == 0)
> -                       vblank->inmodeset |= 0x2;
> -       }
> -}
> -
> -static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
> -                                          unsigned int pipe)
> -{
> -       struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
> -
> -       /* vblank is not initialized (IRQ not installed ?), or has been freed */
> -       if (!drm_dev_has_vblank(dev))
> -               return;
> -
> -       if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
> -               return;
> -
> -       if (vblank->inmodeset) {
> -               spin_lock_irq(&dev->vbl_lock);
> -               drm_reset_vblank_timestamp(dev, pipe);
> -               spin_unlock_irq(&dev->vbl_lock);
> -
> -               if (vblank->inmodeset & 0x2)
> -                       drm_vblank_put(dev, pipe);
> -
> -               vblank->inmodeset = 0;
> -       }
> -}
> -
> -int drm_legacy_modeset_ctl_ioctl(struct drm_device *dev, void *data,
> -                                struct drm_file *file_priv)
> -{
> -       struct drm_modeset_ctl *modeset = data;
> -       unsigned int pipe;
> -
> -       /* If drm_vblank_init() hasn't been called yet, just no-op */
> -       if (!drm_dev_has_vblank(dev))
> -               return 0;
> -
> -       /* KMS drivers handle this internally */
> -       if (!drm_core_check_feature(dev, DRIVER_LEGACY))
> -               return 0;
> -
> -       pipe = modeset->crtc;
> -       if (pipe >= dev->num_crtcs)
> -               return -EINVAL;
> -
> -       switch (modeset->cmd) {
> -       case _DRM_PRE_MODESET:
> -               drm_legacy_vblank_pre_modeset(dev, pipe);
> -               break;
> -       case _DRM_POST_MODESET:
> -               drm_legacy_vblank_post_modeset(dev, pipe);
> -               break;
> -       default:
> -               return -EINVAL;
> -       }
> -
> -       return 0;
> -}
> -
>  static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
>                                   u64 req_seq,
>                                   union drm_wait_vblank *vblwait,
> --
> 2.42.1
>