On Fri, 28 Jan 2011, Chris Wilson wrote:
> On Fri, 28 Jan 2011 08:53:59 -0500 (EST), "Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> wrote:
> > so the culprit appears to be:
> >
> > b705120e4198315f4ae043de06c62f65e0851fd3 is the first bad commit
> > commit b705120e4198315f4ae043de06c62f65e0851fd3
> > Author: Michael Karcher <kernel@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> > Date: Sun Jan 23 18:17:17 2011 +0000
> >
> > drm/i915: Use consistent mappings for OpRegion between ACPI and i915
> >
> > The opregion is a shared memory region between ACPI and the graphics
> > driver. As the ACPI mapping has been changed to cachable in commit
> > 6d5bbf00d251cc73223a71422d69e069dc2e0b8d, mapping the intel opregion
> > non-cachable now fails. As no bus-master hardware is involved in the
> > opregion, cachable map should do no harm.
> >
> > Tested on a Fujitsu Lifebook P8010.
> >
> > Signed-off-by: Michael Karcher <kernel@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> > [ickle: convert to acpi_os_ioremap for consistency]
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> >
> >
> > thoughts? once again, the salient output from "lspci -v":
>
> Indeed looks like using ioremap_cache is not as safe as was assumed. Does
*sigh*. there was, in fact, an "ioremap_error" message displayed
*very* early in the boot sequence, but it was generated even for
successful boots so i never paid it any mind. in hindsight, might
have been useful to have mentioned it.
> diff --git a/include/linux/acpi_io.h b/include/linux/acpi_io.h
> index 7180013..42108ab 100644
> --- a/include/linux/acpi_io.h
> +++ b/include/linux/acpi_io.h
> @@ -7,7 +7,7 @@
> static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
> acpi_size size)
> {
> - return ioremap_cache(phys, size);
> + return ioremap_wc(phys, size);
> }
>
> int acpi_os_map_generic_address(struct acpi_generic_address *addr);
ok, i'll make this single change and report back shortly.
rday
--
========================================================================
Robert P. J. Day Waterloo, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
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