[Spice-devel] [PATCH xf86-video-qxl] Initialize the frame buffer used in dfps mode; this silences a number of valgrind errors.

[Jeremy White]

On 09/19/2014 06:40 AM, Christophe Fergeau wrote:
> Any idea in which situation we are trying to access uninitialized pixmap
> memory?

I no longer recall with precision.  The valgrind trigger was in 
hash_and_copy; I suspect I first encountered it in the case I fixed with 
a later patch (copying past the stride).

However, a prepare_access that doesn't fill the region, or the new 
tuning code I've added to dfps has a clear logical need for a 
preinitialized pixmap, so I think this is correct for a variety of reasons.

Cheers,

Jeremy

> Apart from that, why not.
>
> Christophe
>
> On Fri, Sep 12, 2014 at 02:20:36PM -0500, Jeremy White wrote:
>>
>> Signed-off-by: Jeremy White <jwhite at codeweavers.com>
>> ---
>>   src/dfps.c |   14 ++++++++++++++
>>   1 file changed, 14 insertions(+)
>>
>> diff --git a/src/dfps.c b/src/dfps.c
>> index 5db34dc..568ba5e 100644
>> --- a/src/dfps.c
>> +++ b/src/dfps.c
>> @@ -312,6 +312,17 @@ static void dfps_set_screen_pixmap (PixmapPtr pixmap)
>>       pixmap->drawable.pScreen->devPrivate = pixmap;
>>   }
>>
>> +static void dfps_clear_pixmap(PixmapPtr pixmap, int w, int h)
>> +{
>> +    GCPtr pgc;
>> +    pgc = GetScratchGC(pixmap->drawable.depth, pixmap->drawable.pScreen);
>> +    if (pgc)
>> +    {
>> +        fbFill(&pixmap->drawable, pgc, 0, 0, w, h);
>> +        FreeScratchGC(pgc);
>> +    }
>> +}
>> +
>>   static PixmapPtr dfps_create_pixmap (ScreenPtr screen, int w, int h, int depth, unsigned usage)
>>   {
>>       PixmapPtr pixmap;
>> @@ -324,7 +335,10 @@ static PixmapPtr dfps_create_pixmap (ScreenPtr screen, int w, int h, int depth,
>>
>>       pixmap = fbCreatePixmap (screen, w, h, depth, usage);
>>       if (pixmap)
>> +    {
>> +        dfps_clear_pixmap(pixmap, w, h);
>>           dfps_set_info(pixmap, info);
>> +    }
>>       else
>>           free(info);
>>
>> --
>> 1.7.10.4
>>
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