Re: [PATCH] drm/i915: fix memory corruption with GM965 and >4GB RAM

Chris Wilson
2011-03-01T22:32:24Z

On Tue, 1 Mar 2011 23:24:16 +0100, Jan Niehusmann <jan@gondor.com> wrote:
> Indeed, setting dma_alloc_coherent should be sufficient, AFAIKT. After
> all, only the HWS seems to be affected, which is allocated with
> drm_pci_alloc, which in turn uses dma_alloc_coherent.
>
> I just tried the patch below, it also works for me (as expected). Added
> the comment because otherwise it wouldn't be obvious why the mask gets
> set to 32 bit.
>
> What I don't know is if really only Broadwater and Crestline chips are
> affected. The tests were done with a Crestline one. But I think it's a
> fair guess that the bug would have been noticed earlier if more recent
> chips were affected, as >4GB RAM have become much more common since then.

The later chips do not use a physical address for the hardware status
page. The patch looks good, thanks.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre