[kernel/f13/master] Fix AGP aperture size detection on Intel G33/Q35 chipsets (#629203)

[Chuck Ebbert]

commit 487e4d78da3cf3debe4bebc1022cda5e5196142d
Author: Chuck Ebbert <cebbert at redhat.com>
Date:   Mon Sep 20 08:17:37 2010 -0400

    Fix AGP aperture size detection on Intel G33/Q35 chipsets (#629203)

 ...correct-mask-to-detect-i830-aperture-size.patch |   62 ++++++++++++++++++++
 kernel.spec                                        |    6 ++
 2 files changed, 68 insertions(+), 0 deletions(-)
---
diff --git a/agp-intel-use-the-correct-mask-to-detect-i830-aperture-size.patch b/agp-intel-use-the-correct-mask-to-detect-i830-aperture-size.patch
new file mode 100644
index 0000000..0850df6
--- /dev/null
+++ b/agp-intel-use-the-correct-mask-to-detect-i830-aperture-size.patch
@@ -0,0 +1,62 @@
+From: Tim Gardner <tim.gardner at canonical.com>
+Date: Fri, 9 Jul 2010 20:48:50 +0000 (-0600)
+Subject: agp/intel: Use the correct mask to detect i830 aperture size.
+X-Git-Tag: v2.6.35~33^2~4
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=e7b96f28c58ca09f15f6c2e8ccbb889a30fab4f7
+
+agp/intel: Use the correct mask to detect i830 aperture size.
+
+BugLink: https://bugs.launchpad.net/bugs/597075
+
+commit f1befe71fa7a79ab733011b045639d8d809924ad introduced a
+regression when detecting aperture size of some i915 adapters, e.g.,
+those on the Intel Q35 chipset.
+
+The original report: https://bugzilla.kernel.org/show_bug.cgi?id=15733
+The regression report: https://bugzilla.kernel.org/show_bug.cgi?id=16294
+
+According to the specification found at
+http://intellinuxgraphics.org/VOL_1_graphics_core.pdf, the PCI config
+space register I830_GMCH_CTRL is a mirror of GMCH Graphics
+Control. The correct macro for isolating the aperture size bits is
+therefore I830_GMCH_GMS_MASK along with the attendant changes to the
+case statement.
+
+Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
+Tested-by: Kees Cook <kees.cook at canonical.com>
+Cc: Chris Wilson <chris at chris-wilson.co.uk>
+Cc: Eric Anholt <eric at anholt.net>
+Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
+Signed-off-by: Eric Anholt <eric at anholt.net>
+---
+
+diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
+index 9344216..a754715 100644
+--- a/drivers/char/agp/intel-gtt.c
++++ b/drivers/char/agp/intel-gtt.c
+@@ -1216,17 +1216,20 @@ static int intel_i915_get_gtt_size(void)
+ 
+ 		/* G33's GTT size defined in gmch_ctrl */
+ 		pci_read_config_word(agp_bridge->dev, I830_GMCH_CTRL, &gmch_ctrl);
+-		switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) {
+-		case G33_PGETBL_SIZE_1M:
++		switch (gmch_ctrl & I830_GMCH_GMS_MASK) {
++		case I830_GMCH_GMS_STOLEN_512:
++			size = 512;
++			break;
++		case I830_GMCH_GMS_STOLEN_1024:
+ 			size = 1024;
+ 			break;
+-		case G33_PGETBL_SIZE_2M:
+-			size = 2048;
++		case I830_GMCH_GMS_STOLEN_8192:
++			size = 8*1024;
+ 			break;
+ 		default:
+ 			dev_info(&agp_bridge->dev->dev,
+ 				 "unknown page table size 0x%x, assuming 512KB\n",
+-				(gmch_ctrl & G33_PGETBL_SIZE_MASK));
++				(gmch_ctrl & I830_GMCH_GMS_MASK));
+ 			size = 512;
+ 		}
+ 	} else {
diff --git a/kernel.spec b/kernel.spec
index 057bb36..9f52838 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -713,6 +713,7 @@ Patch1826: drm-radeon-resume-fixes.patch
 Patch1830: drm-i915-explosion-following-oom-in-do_execbuffer.patch
 Patch1900: linux-2.6-intel-iommu-igfx.patch
 Patch1901: drm-nouveau-acpi-edid-fix.patch
+Patch1902: agp-intel-use-the-correct-mask-to-detect-i830-aperture-size.patch
 # radeon
 
 # linux1394 git patches
@@ -1404,6 +1405,8 @@ ApplyPatch drm-intel-big-hammer.patch
 ApplyOptionalPatch drm-intel-next.patch
 ApplyPatch drm-intel-make-lvds-work.patch
 ApplyPatch drm-i915-explosion-following-oom-in-do_execbuffer.patch
+# broken in 2.6.35-rc2, fixed in 2.6.35, but our drm-next snapshot has the bug
+ApplyPatch agp-intel-use-the-correct-mask-to-detect-i830-aperture-size.patch
 
 ApplyPatch drm-radeon-resume-fixes.patch
 ApplyPatch linux-2.6-intel-iommu-igfx.patch
@@ -2146,6 +2149,9 @@ fi
 
 
 %changelog
+* Mon Sep 20 2010 Chuck Ebbert <cebbert at redhat.com>
+- Fix AGP aperture size detection on Intel G33/Q35 chipsets (#629203)
+
 * Tue Sep 14 2010 Chuck Ebbert <cebbert at redhat.com> 2.6.34.7-57
 - Fix CVE-2010-3079: ftrace NULL pointer dereference