fbComposite bugs

Matthias Hopf mhopf at suse.de
Thu Feb 2 10:24:10 PST 2006


I described some bugs I stumbled upon during fixing the XAAComposite
fastpath and documented them in bugzilla 5796.

Before committing anything here I'd like to hear comments /
contradictions / corrections.

Thanks

Matthias

-- 
Matthias Hopf <mhopf at suse.de>       __        __   __
Maxfeldstr. 5 / 90409 Nuernberg    (_   | |  (_   |__         mat at mshopf.de
Phone +49-911-74053-715            __)  |_|  __)  |__  labs   www.mshopf.de
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During investigation of bug #4320 I found several bugs in fbComposite, which
*accidentially* actually accelerated the copy process. In these corner cases no
harm was done, but it could be possible.

This bug is here for tracking and for discussion whether I'm right here.

1st) fbpict.c:845
     Bool srcRepeat = pSrc->pDrawable && pSrc->repeat == RepeatNormal;
  should IMHO read (RepeatPad & RepeatReflect weren't honored)
     Bool srcRepeat = pSrc->pDrawable && pSrc->repeat;

2nd) fbpict.c:893 & 1068
   The else part of
      if (srcRepeat &&
          pSrc->pDrawable->width == 1 &&
          pSrc->pDrawable->height == 1)
   labels /* has mask and non-repeating source */
   but is also hit if width or height are != 1. In these cases AFACS
   the slow path should be taken.
   Perhaps the same methology as in bug #4320 could be used for
   improving the number of fast path cases.

Any thoughts?


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