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authorDaniel Vetter <daniel.vetter@ffwll.ch>2014-05-08 15:39:19 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2014-05-21 11:31:00 +0200
commit8edffbb933619d568ea98edd3b55ec7c30df9274 (patch)
tree2f0214456eff61be5d4cc6b296da4f893d3360c5 /Documentation/DocBook
parentadd1d00823a820f8244c88407d7112d4a66e70c8 (diff)
drm/doc: Discourage usage of MODESET_CTL ioctl
Leftover from the old days of ums and should be used any longer. Since commit 29935554b384b1b3a7377d6f0b03b21d18a61683 Author: Laurent Pinchart <laurent.pinchart@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@ideasonboard.com> Cc: Michel Dänzer <michel@daenzer.net> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/drm.tmpl12
1 files changed, 6 insertions, 6 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index ec81c20a17d..ad93c3e6b85 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -2861,12 +2861,12 @@ int num_ioctls;</synopsis>
<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).
+ 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.
</para>
</listitem>
</varlistentry>