[PATCH 1/2] DRI2: Avoid call to NULL pointer

[Pauli Nieminen]

On 07/10/10 00:42 +0200, ext Mario Kleiner wrote:
> On Oct 6, 2010, at 1:05 PM, Pauli Nieminen wrote:
> 
> > DDX driver may implement schedule swap without GetMSC. In that case we
> > can't call GetMSC in DRI2SwapBuffers.
> >
> 
> I don't think this check is neccessary. Afaik if the ds->GetMSC entry  
> point isn't defined then ds->ScheduleSwap isn't defined either, so  
> the !ds->ScheduleSwap  check at the beginning of the routine triggers  
> and the fallback path is taken, no?
> 

no. It is perfectly valid to have ScheduleSwap without GetMSC. This is
important for driver that can implement page flipping but doesn't have simple
way to expose msc count.

> -mario
> 
> > Signed-off-by: Pauli Nieminen <ext-pauli.nieminen at nokia.com>
> > ---
> >  hw/xfree86/dri2/dri2.c |   11 +++++++----
> >  1 files changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
> > index 228c0e0..d9b9d57 100644
> > --- a/hw/xfree86/dri2/dri2.c
> > +++ b/hw/xfree86/dri2/dri2.c
> > @@ -856,11 +856,14 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr  
> > pDraw, CARD64 target_msc,
> >  	 * is moved to a crtc with a lower refresh rate, or a crtc that just
> >  	 * got enabled.
> >  	 */
> > -	if (!(*ds->GetMSC)(pDraw, &ust, &current_msc))
> > -	    pPriv->last_swap_target = 0;
> > +	if (ds->GetMSC) {
> > +	    if (!(*ds->GetMSC)(pDraw, &ust, &current_msc))
> > +		pPriv->last_swap_target = 0;
> >
> > -	if (current_msc < pPriv->last_swap_target)
> > -	    pPriv->last_swap_target = current_msc;
> > +	    if (current_msc < pPriv->last_swap_target)
> > +		pPriv->last_swap_target = current_msc;
> > +
> > +	}
> >
> >  	/*
> >  	 * Swap target for this swap is last swap target + swap interval  
> > since
> > -- 
> > 1.7.0.4
> >
> > _______________________________________________
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> 
> *********************************************************************
> Mario Kleiner
> Max Planck Institute for Biological Cybernetics
> Spemannstr. 38
> 72076 Tuebingen
> Germany
> 
> e-mail: mario.kleiner at tuebingen.mpg.de
> office: +49 (0)7071/601-1623
> fax:    +49 (0)7071/601-616
> www:    http://www.kyb.tuebingen.mpg.de/~kleinerm
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