Re: [PATCH 06/12] drm/doc: Discourage usage of MODESET_CTL ioctl

On 15.05.2014 03:51, Daniel Vetter wrote:

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.

Cc: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch

---

Documentation/DocBook/drm.tmpl | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 83dd0b043c28..e37a77a72b8b 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -2861,12 +2861,11 @@ 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.
  

This sentence looks mangled pretty badly. Did you have something like this in mind?

"This was only used for user-mode-setting drivers around modesetting changes to allow the kernel to keep the vertical blank counters consistent, since on many devices the hardware vertical blank counter is reset to 0 at some point during modeset changes."