diff options
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/drm.tmpl | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index da011f2..457d56a 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -619,23 +619,34 @@ void intel_crt_init(struct drm_device *dev) <title>VBlank event handling</title> <para> The DRM core exposes two vertical blank related ioctls: - DRM_IOCTL_WAIT_VBLANK and DRM_IOCTL_MODESET_CTL. + <variablelist> + <varlistentry> + <term>DRM_IOCTL_WAIT_VBLANK</term> + <listitem> + <para> + 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. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>DRM_IOCTL_MODESET_CTL</term> + <listitem> + <para> + 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). + </para> + </listitem> + </varlistentry> + </variablelist> <!--!Edrivers/char/drm/drm_irq.c--> </para> <para> - 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. - </para> - <para> - 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). - </para> - <para> To support the functions above, the DRM core provides several helper functions for tracking vertical blank counters, and requires drivers to provide several callbacks: |