On Mi, 2017-01-11 at 16:59 +0200, Alberto Garcia wrote:
> On Mon, Nov 28, 2016 at 11:52:08AM +0530, P J P wrote:
> > | > --- a/hw/display/cirrus_vga.c
> > | > +++ b/hw/display/cirrus_vga.c
> > | > @@ -272,6 +272,9 @@ static void
> > cirrus_update_memory_access(CirrusVGAState
> > | > *s);
> > | > static bool blit_region_is_unsafe(struct CirrusVGAState *s,
> > | > int32_t pitch, int32_t addr)
> > | > {
> > | > + if (!pitch) {
> > | > + return true;
> > | > + }
> > | >
> > |
> > | That doesn't look directly related to 'cirrus_get_bpp', care to explain?
> >
> > 'blit_region_is_unsafe' is called from 'blit_is_unsafe' to check if blit
> > parameters (cirrus_blt_srcpitch/cirrus_blt_dstpitch) are safe for
> > 'cirrus_do_copy'. These too could lead to div by zero in cirrus_do_copy
>
> This change is causing display artifacts in QEMU 2.8.
>
> What seems to happen is that blit_is_unsafe() is also called for
> CIRRUS_BLTMODE_PATTERNCOPY, but in this case cirrus_blt_srcpitch is
> not used. However, because of this new check if its value is 0 then
> cirrus_bitblt_common_patterncopy() returns early and becomes a no-op.
inflight vga queue pull request has a fix for that.
cheers,
Gerd
