On Sun, Jun 28, 2015 at 09:19:26AM +0100, Chris Wilson wrote: > The old style of memory interleaving swizzled upto the end of the > first even bank of memory, and then used the remainder as unswizzled on > the unpaired bank - i.e. swizzling is not constant for all memory. This > causes problems when we try to migrate memory and so the kernel prevents > migration at all when we detect L-shaped inconsistent swizzling. > However, this issue also extends to userspace who try to manually detile > into memory as the swizzling for an individual page is unknown (it > depends on its physical address only known to the kernel), userspace > cannot correctly swizzle. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91105 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > drivers/gpu/drm/i915/i915_gem_tiling.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c > index d16585f788ea..ff96ae9b77bc 100644 > --- a/drivers/gpu/drm/i915/i915_gem_tiling.c > +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c > @@ -447,7 +447,10 @@ i915_gem_get_tiling(struct drm_device *dev, void *data, > } > > /* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */ > - args->phys_swizzle_mode = args->swizzle_mode; > + if (dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) > + args->phys_swizzle_mode = I915_BIT_6_SWIZZLE_UNKNOWN; > + else > + args->phys_swizzle_mode = args->swizzle_mode; It may be better to store the dev_priv->mm.bit_6_swizzle_[xy] as UNKNOWN for L-shaped memory. I think that would be more correct. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html