On Fri, 04 Sep 2015 14:29:22 +0100 "Ben Avison" <bavi...@riscosopen.org> wrote:
> On Fri, 04 Sep 2015 11:18:03 +0100, Pekka Paalanen <ppaala...@gmail.com> > wrote: > > I think we may have a problem with sizes/coordinates. > > > > With 64 kB page size, the minimum fenced image width for r5g6b5 image > > is 32768 pixels. GDB tells me src_img->bits.width << 16 is negative. > > > > Similarly the minimum width of an a8 image becomes 64k pixels. These > > coordinates do not fit in pixman_fixed_t. > > This is a good point. > > However, I have thought of a workaround. Only the image width is > constrained to be < 65536 (or < 32768 if we want to avoid signed issues, > since pixman_fixed_t is defined to be a signed quantity). The *stride* > isn't. > In the case where the page size is much larger than a row, this amounts to > alternating protected and unprotected pages. Then we set the stride to > the distance between protected pages, and set image->bits.bits such that > either the left or right edge of each row lines up with the page boundary. > Obviously that would require work to the fence image code as well as to > cover-test, so I thought I'd ask for opinions - is it worth the added > complexity, or should we just bail out if the page size is > 32K as Pekka > suggests? My opinion is that let's get this test landed now with skip on too large page size, and enchance it later if wanted. Ben, shall I add the skips and bikeshed with style and send the cover-test patch to the list once more? Thanks, pq
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