Re: [Intel-gfx] [PATCH v2 12/25] i915: switch from acpi_os_ioremap to ioremap

Daniel Vetter
2015-07-27T07:48:14Z

On Fri, Jul 24, 2015 at 10:39:04PM -0400, Dan Williams wrote:
> acpi_os_ioremap uses cached mappings, however it appears that i915
> wants to read dynamic platform state. Switch to ioremap() to prevent it
> reading stale state from cache.
>
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: David Airlie <airlied@linux.ie>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> drivers/gpu/drm/i915/intel_opregion.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
> index 481337436f72..16ba7c67410d 100644
> --- a/drivers/gpu/drm/i915/intel_opregion.c
> +++ b/drivers/gpu/drm/i915/intel_opregion.c
> @@ -863,7 +863,7 @@ int intel_opregion_setup(struct drm_device *dev)
> INIT_WORK(&opregion->asle_work, asle_work);
> #endif
>
> - base = acpi_os_ioremap(asls, OPREGION_SIZE);
> + base = ioremap(asls, OPREGION_SIZE);

OpRegion is cached memory shared with the firmware afaik, we probably want
a memremap here and switch away from the ioread/write stuff. We have a
similar confusion going on for the vbt parsing (which on anything but
really old machines is also just normal memory).

Same holds for gma500, which is just a copy of i915 for some special
platforms.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation