From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-1?Q?Michel_D=E4nzer?= <michel@daenzer.net>
Subject: Re: [PATCH 06/12] drm/doc: Discourage usage of
	MODESET_CTL ioctl
Date: Thu, 15 May 2014 13:27:54 +0900
Message-ID: <5374424A.2070005@daenzer.net>
References: <1400093477-3217-1-git-send-email-daniel.vetter@ffwll.ch>
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To: Daniel Vetter <daniel.vetter@ffwll.ch>, DRI Development <dri-devel@lists.freedesktop.org>, Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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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.t=
mpl
> 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 befor=
e and
> -                after mode setting, since on many devices the vertical b=
lank
> -                counter is reset at that time.  Internally, the DRM snap=
shots
> -                the last vblank count when the ioctl is called with the
> -                _DRM_PRE_MODESET command, so that the counter won't go b=
ackwards
> -                (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."


-- =

Earthling Michel D=E4nzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer