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

[Laurent Pinchart]

Hi Daniel,

Thank you for the patch.

On Thursday 15 May 2014 15:00:08 Daniel Vetter wrote:
> Leftover from the old days of ums and should be used any longer. Since
> 
> commit 29935554b384b1b3a7377d6f0b03b21d18a61683
> 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>

Acked-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  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
> --- 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>

-- 
Regards,

Laurent Pinchart