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>

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index c3889189254774cd1de84a26c0153d1146adfa9f..a2045848bd1a3d5d37c299d34b7e19dce50173d7 100644 (file)
--- 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;