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Commit 8edffbb9 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/doc: Discourage usage of MODESET_CTL ioctl 



Leftover from the old days of ums and should be used any longer. Since

commit 29935554
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: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent add1d008

Documentation/DocBook/drm.tmpl

+6 −6
Original line number Diff line number Diff line
@@ -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>