The pageflip semantics documentation was tailored to Intel hardware, where pageflips are done by banging on registers. Many GPUs have the possibilities to send pageflips down the command stream, and the driver command submission mechanism does not have to block in order to order page-flip and command execution. Also remove the sync-to-vblank requirement. Some hardware doesn't support it, and it might not be desired in all situations either. I think all this was brought up on the DRI-devel email list on the pageflip ioctl design discussion.
Signed-off-by: Thomas Hellstrom thellstrom@vmware.com --- include/drm/drm_mode.h | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/drm/drm_mode.h b/include/drm/drm_mode.h index 9006b93..d88ef35 100644 --- a/include/drm/drm_mode.h +++ b/include/drm/drm_mode.h @@ -327,9 +327,9 @@ struct drm_mode_crtc_lut { * This ioctl will ask KMS to schedule a page flip for the specified * crtc. Once any pending rendering targeting the specified fb (as of * ioctl time) has completed, the crtc will be reprogrammed to display - * that fb after the next vertical refresh. The ioctl returns - * immediately, but subsequent rendering to the current fb will block - * in the execbuffer ioctl until the page flip happens. If a page + * that fb. The ioctl returns immediately, and subsequently queued rendering + * to any of the involved fbs will be ordered with the page flip so that it + * occurs after the page-flip is ececuted by the hardware. If a page * flip is already pending as the ioctl is called, EBUSY will be * returned. *