On Wed, 14 Nov 2012 21:19:05 +0000 Alan Cox <alan at lxorguk.ukuu.org.uk> wrote: > On Wed, 14 Nov 2012 20:43:31 +0000 > Jesse Barnes <jbarnes at virtuousgeek.org> wrote: > > > SNB graphics devices have a bug that prevent them from accessing certain > > memory ranges, namely anything below 1M and in the pages listed in the > > table. So reserve those at boot if set detect a SNB gfx device on the > > CPU to avoid GPU hangs. > > What happens if the other addresses map to an external memory object - eg > a PCI device which is a legitimate DMA source for video overlay etc ? Other addresses as in the 5 pages high in the address space? I'm not sure how to do what I want with memblock, doesn't it just allocate RAM not I/O space?... /me looks at the memblock API Or do you mean if we map GTT pages to point at some non-RAM region will SNB gfx be able to decode them? If that's the question, then I think the answer is no, but I don't have enough detail on the hw bug to be certain. > I assume this is just for GPU fetches from main memory ? AIUI, it's an address decoder bug, so it would affect any fetch by the GPU through its memory interface glue. -- Jesse Barnes, Intel Open Source Technology Center
