[PATCH/RFC] drm: Disallow DRM_IOCTL_MODESET_CTL for KMS drivers

Laurent Pinchart laurent.pinchart at ideasonboard.com
Wed May 30 10:12:11 PDT 2012


Hi Michel,

On Wednesday 30 May 2012 13:29:06 Michel Dänzer wrote:
> On Mit, 2012-05-30 at 00:58 +0200, Laurent Pinchart wrote:
> > DRM_IOCTL_MODESET_CTL must only be used for UMS drivers. Make it a no-op
> > for KMS drivers.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> > 
> >  drivers/gpu/drm/drm_irq.c |    5 ++++-
> >  1 files changed, 4 insertions(+), 1 deletions(-)
> > 
> > My understanding of the DRM framework tells me that calling
> > DRM_IOCTL_MODESET_CTL on a KMS driver is not only unneeded, but could also
> > mess up its internal state. Did I get it right ?
> 
> Yes, good catch.
> 
> > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> > index c798eea..03f16f3 100644
> > --- a/drivers/gpu/drm/drm_irq.c
> > +++ b/drivers/gpu/drm/drm_irq.c
> > @@ -974,7 +974,6 @@ EXPORT_SYMBOL(drm_vblank_off);
> > 
> >   * drm_vblank_pre_modeset - account for vblanks across mode sets
> >   * @dev: DRM device
> >   * @crtc: CRTC in question
> > - * @post: post or pre mode set?
> >   *
> >   * Account for vblank events across mode setting events, which will
> >   likely
> >   * reset the hardware frame counter.
> 
> This hunk should really be in a separate patch,

I've thought about sending a separate patch, but as the change only touched a 
single line of comment related to the same function, I ended up not splitting 
it. I can resubmit two patches if needed.

> but other than that
> 
> Reviewed-by: Michel Dänzer <michel at daenzer.net>

Thank you.

-- 
Regards,

Laurent Pinchart



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