Re: [PATCH 3/3] drm: Add CRTC_GET_SEQUENCE and CRTC_QUEUE_SEQUENCE ioctls [v2]
From: Michel DÃnzer
Date: Wed Aug 02 2017 - 05:45:44 EST
On 01/08/17 02:03 PM, Keith Packard wrote:
> These provide crtc-id based functions instead of pipe-number, while
> also offering higher resolution time (ns) and wider frame count (64)
> as required by the Vulkan API.
> * Check for DRIVER_MODESET in new crtc-based vblank ioctls
> Failing to check this will oops the driver.
> * Ensure vblank interupt is running in crtc_get_sequence ioctl
> The sequence and timing values are not correct while the
> interrupt is off, so make sure it's running before asking for
> * Short-circuit get_sequence if the counter is enabled and accurate
> Steal the idea from the code in wait_vblank to avoid the
> expense of drm_vblank_get/put
> * Return active state of crtc in crtc_get_sequence ioctl
> Might be useful for applications that aren't in charge of
> * Use drm_crtc_vblank_get/put in new crtc-based vblank sequence ioctls
> Daniel Vetter prefers these over the old drm_vblank_put/get
> * Return s64 ns instead of u64 in new sequence event
> Suggested-by: Daniel Vetter <daniel@xxxxxxxx>
> Suggested-by: Ville SyrjÃlÃ <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
> +#define DRM_CRTC_SEQUENCE_NEXT_ON_MISS 0x00000002 /* Use next sequence if we've missed */
Do you have userspace making use of DRM_CRTC_SEQUENCE_NEXT_ON_MISS? If
not, drop it.
> +#define DRM_CRTC_SEQUENCE_FIRST_PIXEL_OUT 0x00000004 /* Signal when first pixel is displayed */
I thought there was consensus that this flag is pointless.
Earthling Michel DÃnzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer