[PATCH] drm/doc: Discourage usage of MODESET_CTL ioctl
daniel.vetter at ffwll.ch
Thu May 15 06:00:08 PDT 2014
Leftover from the old days of ums and should be used any longer. Since
Author: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Date: Wed May 30 00:58:09 2012 +0200
drm: Disallow DRM_IOCTL_MODESET_CTL for KMS drivers
it is a complete no-Op for kms drivers.
v2: Fix up mangled sentence spotted by Michel.
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Michel Dänzer <michel at daenzer.net>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Documentation/DocBook/drm.tmpl | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 83dd0b043c28..96cee6438472 100644
@@ -2861,12 +2861,12 @@ int num_ioctls;</synopsis>
- 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).
+ This was only used for user-mode-settind drivers around
+ modesetting changes to allow the kernel to update the vblank
+ interrupt after mode setting, since on many devices the vertical
+ blank counter is reset to 0 at some point during modeset. Modern
+ drivers should not call this any more since with kernel mode
+ setting it is a no-op.
More information about the dri-devel