From: Daniel Vetter Date: Thu, 8 May 2014 13:39:19 +0000 (+0200) Subject: drm/doc: Discourage usage of MODESET_CTL ioctl X-Git-Tag: next-20140530~66^2~69^2~5 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8edffbb933619d568ea98edd3b55ec7c30df9274;p=karo-tx-linux.git 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 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 Cc: Michel Dänzer Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter --- diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index ec81c20a17db..ad93c3e6b859 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -2861,12 +2861,12 @@ int num_ioctls; 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). + 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.