On Mon, 3 Mar 2014 11:14:09 -0800
Jesse Barnes <jbar...@virtuousgeek.org> wrote:
> On Thu, 27 Feb 2014 11:01:08 +0200
> Jani Nikula <jani.nik...@linux.intel.com> wrote:
>
> > On Thu, 27 Feb 2014, Jani Nikula <jani.nik...@linux.intel.com> wrote:
> > > On Wed, 26 Feb 2014, Jesse Barnes <jbar...@virtuousgeek.org> wrote:
> > >> On Mon, 13 Jan 2014 16:25:21 +0530
> > >> akash.g...@intel.com wrote:
> > >>
> > >>> From: Akash Goel <akash.g...@intel.com>
> > >>>
> > >>> There is a conflict seen when requesting the kernel to reserve
> > >>> the physical space used for the stolen area. This is because
> > >>> some BIOS are wrapping the stolen area in the root PCI bus, but have
> > >>> an off-by-one error. As a workaround we retry the reservation with an
> > >>> offset of 1 instead of 0.
> > >>>
> > >>> v2: updated commit message & the comment in source file (Daniel)
> > >>>
> > >>> Signed-off-by: Akash Goel <akash.g...@intel.com>
> > >>> ---
> > >>> drivers/gpu/drm/i915/i915_gem_stolen.c | 20 +++++++++++++++++---
> > >>> 1 file changed, 17 insertions(+), 3 deletions(-)
> > >>>
> > >>> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c
> > >>> b/drivers/gpu/drm/i915/i915_gem_stolen.c
> > >>> index 1a24e84..114a806 100644
> > >>> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> > >>> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> > >>> @@ -82,9 +82,23 @@ static unsigned long i915_stolen_to_physical(struct
> > >>> drm_device *dev)
> > >>> r = devm_request_mem_region(dev->dev, base,
> > >>> dev_priv->gtt.stolen_size,
> > >>> "Graphics Stolen Memory");
> > >>> if (r == NULL) {
> > >>> - DRM_ERROR("conflict detected with stolen region:
> > >>> [0x%08x - 0x%08x]\n",
> > >>> - base, base +
> > >>> (uint32_t)dev_priv->gtt.stolen_size);
> > >>> - base = 0;
> > >>> + /*
> > >>> + * One more attempt but this time requesting region from
> > >>> + * base + 1, as we have seen that this resolves the
> > >>> region
> > >>> + * conflict with the PCI Bus.
> > >>> + * This is a BIOS w/a: Some BIOS wrap stolen in the root
> > >>> + * PCI bus, but have an off-by-one error. Hence retry
> > >>> the
> > >>> + * reservation starting from 1 instead of 0.
> > >>> + */
> > >>> + r = devm_request_mem_region(dev->dev, base + 1,
> > >>> + dev_priv->gtt.stolen_size -
> > >>> 1,
> > >>> + "Graphics Stolen Memory");
> > >>> + if (r == NULL) {
> > >>> + DRM_ERROR("conflict detected with stolen
> > >>> region:"\
> > >>> + "[0x%08x - 0x%08x]\n",
> > >>> + base, base +
> > >>> (uint32_t)dev_priv->gtt.stolen_size);
> > >>> + base = 0;
> > >>> + }
> > >>> }
> > >>>
> > >>> return base;
> > >>
> > >> Reviewed-by: Jesse Barnes <jbar...@virtuousgeek.org>
> > >> Tested-by: Arjan van de Ven <ar...@linux.intel.com>
> > >
> > > Pushed to -fixes, thanks for the patch, review, and testing.
> >
> > Oh, forgot to add that I fixed the DRM_ERROR string split up that
> > checkpatch complained about while applying.
>
> Note I think we should do this at the x86 quirk level as well since
> otherwise the kernel may put MMIO space on top of our stolen range.
Nevermind, I think the stolen core code will do the right thing and
mark this region reserved... but it's worth checking on an affected
system.
--
Jesse Barnes, Intel Open Source Technology Center
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