drm/i915: Don't complain about stolen conflicts on gen3

Apparently stuff works that way on those machines.

I agree with Chris' concern that this is a bit risky but imo worth a
shot in -next just for fun. Afaics all these machines have the pci
resources allocated like that by the BIOS, so I suspect that it's all
ok.

This regression goes back to

commit eaba1b8f3379b5d100bd146b9a41d28348bdfd09
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Jul 4 12:28:35 2013 +0100

    drm/i915: Verify that our stolen memory doesn't conflict

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76983
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71031
Tested-by: lu hua <huax.lu@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Paul Menzel <paulepanter@users.sourceforge.net>
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index c38891892547..a2045848bd1a 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -137,7 +137,11 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
                 r = devm_request_mem_region(dev->dev, base + 1,
                                             dev_priv->gtt.stolen_size - 1,
                                             "Graphics Stolen Memory");
-                if (r == NULL) {
+                /*
+                 * GEN3 firmware likes to smash pci bridges into the stolen
+                 * range. Apparently this works.
+                 */
+                if (r == NULL && !IS_GEN3(dev)) {
                         DRM_ERROR("conflict detected with stolen region: [0x%08x - 0x%08x]\n",
                                   base, base + (uint32_t)dev_priv->gtt.stolen_size);
                         base = 0;