Hello Zack,
Thanks for your patch.
Zack Rusin <zack@xxxxxxx> writes:
> From: Zack Rusin <zackr@xxxxxxxxxx>
>
> Many drivers (in particular all of the virtualized drivers) do not
> implement vblank handling. Assuming vblank is always present
> leads to crashes.
>
> Fix the crashes by making sure the device supports vblank before using
> it.
>
[...]
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index 299fa2a19a90..6438aeb1c65f 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -997,12 +997,16 @@ int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime)
> {
> unsigned int pipe = drm_crtc_index(crtc);
> struct drm_vblank_crtc *vblank = &crtc->dev->vblank[pipe];
> - struct drm_display_mode *mode = &vblank->hwmode;
> + struct drm_display_mode *mode;
> u64 vblank_start;
>
> + if (!drm_dev_has_vblank(crtc->dev))
> + return -EINVAL;
> +
> if (!vblank->framedur_ns || !vblank->linedur_ns)
> return -EINVAL;
>
> + mode = &vblank->hwmode;
> if (!drm_crtc_get_last_vbltimestamp(crtc, vblanktime, false))
> return -EINVAL;
>
Rob already posted more or less the same fix:
https://lore.kernel.org/lkml/CAF6AEGsdT95-uAKcv2+hdMLKd2xwfPeN+FMuDTRMc-Ps7WbRjw@xxxxxxxxxxxxxx/T/
--
Best regards,
Javier Martinez Canillas
Core Platforms
Red Hat
