From 51b9500de28a1e5e7a2090de5d345d6d98581617 Mon Sep 17 00:00:00 2001 From: Michael Witten Date: Thu, 25 Aug 2011 21:11:30 +0000 Subject: [PATCH] DocBook/drm: Use a for vblank ioctls Signed-off-by: Michael Witten --- Documentation/DocBook/drm.tmpl | 39 ++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index da011f2af9cb..457d56a1a966 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -619,22 +619,33 @@ void intel_crt_init(struct drm_device *dev) VBlank event handling The DRM core exposes two vertical blank related ioctls: - DRM_IOCTL_WAIT_VBLANK and DRM_IOCTL_MODESET_CTL. + + + DRM_IOCTL_WAIT_VBLANK + + + This takes a struct drm_wait_vblank structure as its argument, + and it is used to block or request a signal when a specified + vblank event occurs. + + + + + DRM_IOCTL_MODESET_CTL + + + This should be called by application level drivers before and + after mode setting, since on many devices the vertical blank + counter is reset at that time. Internally, the DRM snapshots + the last vblank count when the ioctl is called with the + _DRM_PRE_MODESET command so that the counter won't go backwards + (which is dealt with when _DRM_POST_MODESET is used). + + + + - - DRM_IOCTL_WAIT_VBLANK takes a struct drm_wait_vblank structure - as its argument, and is used to block or request a signal when a - specified vblank event occurs. - - - DRM_IOCTL_MODESET_CTL should be called by application level - drivers before and after mode setting, since on many devices, the - vertical blank counter is reset at that time. Internally, - the DRM snapshots the last vblank count when the ioctl is called - with the _DRM_PRE_MODESET command so that the counter won't go - backwards (which is dealt with when _DRM_POST_MODESET is used). - To support the functions above, the DRM core provides several helper functions for tracking vertical blank counters, and