* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, uv: Ensure hub revision set for all ACPI modes.
x86, uv: Add function retrieving node controller revision number
x86: xen: 64-bit kernel RPL should be 0
x86: kernel_thread() -- initialize SS to a known state
x86/agp: Fix agp_amd64_init and agp_amd64_cleanup
x86: SGI UV: Fix mapping of MMIO registers
x86: mce.h: Fix warning in header checks
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
drm/i915: enable 36bit physical address for hardware status page
drm/i915: fix eDP pipe mask
drm/i915: fix pixel color depth setting on eDP
drm/i915: parse eDP panel color depth from VBT block
drm/i915: disable LVDS downclock by default
drm/i915: Fix the incorrect cursor A bit definition in DSPFW2 register
drm/i915: Remove chatty execbuf failure message.
drm/i915: remove loop in Ironlake interrupt handler
drm/i915: Don't wait interruptible for possible plane buffer flush
drm/i915: try another possible DDC bus for the SDVO device with multiple outputs
drm/i915: Read the response after issuing DDC bus switch command
drm/i915: Don't use the child device parsed from VBT to setup HDMI/DP
drm/i915: Fix resume regression on MSI Wind U100 w/o KMS
drm/i915: Fix Ironlake M/N/P ranges to match the spec
drm/i915: Use find_pll function to calculate DPLL setting for LVDS downclock
drm/i915: Add HP nx9020/SamsungSX20S to ACPI LID quirk list
drm/i915: disable TV hotplug status check
Trivial conflicts in drivers/gpu/drm/i915/i915_drv.c due to i915
non-modeset suspend fix with different comment.
This enables possible 36bit address mask on 965G that use physical
address for hw status page.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
This fixes the regression introduced by the commit
f405d2c023.
The above commit fixes the following issue:
http://marc.info/?l=linux-kernel&m=126192729110083&w=2
However, it doesn't work properly when you remove and insert the
agp_amd64 module again.
agp_amd64_init() and agp_amd64_cleanup should be called only
when gart_iommu is not called earlier (that is, the GART IOMMU
is not enabled). We need to use 'gart_iommu_aperture' to see if
GART IOMMU is enabled or not.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: mitov@issp.bas.bg
Cc: davej@redhat.com
LKML-Reference: <20100104161603L.fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'agp-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/agp-2.6:
agp/hp: fail gracefully if we don't find an IOC
agp/hp: fixup hp agp after ACPI changes
agp: correct missing cleanup on error in agp_add_bridge
Bail out if we don't find an enclosing IOC. Previously, if we didn't
find one, we tried to set things up using garbage for the SBA/IOC register
address, which causes a crash.
This crash only happens if firmware supplies a defective ACPI namespace, so
it doesn't fix any problems in the field.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Commit 15b8dd53f5 changed the string in info->hardware_id from a static
array to a pointer and added a length field. But instead of changing
"sizeof(array)" to "length", we changed it to "sizeof(length)" (== 4),
which corrupts the string we're trying to null-terminate.
We no longer even need to null-terminate the string, but we *do* need to
check whether we found a HID. If there's no HID, we used to have an empty
array, but now we have a null pointer.
The combination of these defects causes this oops:
Unable to handle kernel NULL pointer dereference (address 0000000000000003)
modprobe[895]: Oops 8804682956800 [1]
ip is at zx1_gart_probe+0xd0/0xcc0 [hp_agp]
http://marc.info/?l=linux-ia64&m=126264484923647&w=2
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reported-by: Émeric Maschino <emeric.maschino@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
While investigating a kmemleak detected leak, I encountered the
agp_add_bridge function. It appears to be responsible for freeing
the agp_bridge_data in the case of a failure, but it is only doing
so for some errors.
Fix it to always free the bridge data if a failure condition is
encountered.
Signed-off-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
with CONFIG_GART_IOMMU enabled drivers/char/agp/amd64-agp.c has:
#ifndef CONFIG_GART_IOMMU
module_init(agp_amd64_init);
module_exit(agp_amd64_cleanup);
#endif
agp_amd64_init() was called via gart_iommu_init with
CONFIG_GART_IOMMU=y agp_amd64_init() was called via module_init
with CONFIG_GART_IOMMU=n
The commit 75f1cdf1dd changes the
x86 dma initialization routine: gart_iommu_init() is called only
when GART IOMMU is detected. So when GART IOMMU isn't detected,
agp_amd64_init isn't called.
Marin Mitov reported this issue:
http://marc.info/?l=linux-kernel&m=126192729110083&w=2
With this patch, agp_amd64_init() is always called via
module_init (the above ifndef is removed). If agp_amd64_init()
is called via gart_iommu_init() earlier, agp_amd64_init()
finishes without doing anything (when it is called via
module_init).
Reported-by: Marin Mitov <mitov@issp.bas.bg>
Tested-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: davej@redhat.com
LKML-Reference: <20091228181118C.fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (151 commits)
powerpc: Fix usage of 64-bit instruction in 32-bit altivec code
MAINTAINERS: Add PowerPC patterns
powerpc/pseries: Track previous CPPR values to correctly EOI interrupts
powerpc/pseries: Correct pseries/dlpar.c build break without CONFIG_SMP
powerpc: Make "intspec" pointers in irq_host->xlate() const
powerpc/8xx: DTLB Miss cleanup
powerpc/8xx: Remove DIRTY pte handling in DTLB Error.
powerpc/8xx: Start using dcbX instructions in various copy routines
powerpc/8xx: Restore _PAGE_WRITETHRU
powerpc/8xx: Add missing Guarded setting in DTLB Error.
powerpc/8xx: Fixup DAR from buggy dcbX instructions.
powerpc/8xx: Tag DAR with 0x00f0 to catch buggy instructions.
powerpc/8xx: Update TLB asm so it behaves as linux mm expects.
powerpc/8xx: Invalidate non present TLBs
powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate
pseries/pseries: Add code to online/offline CPUs of a DLPAR node
powerpc: stop_this_cpu: remove the cpu from the online map.
powerpc/pseries: Add kernel based CPU DLPAR handling
sysfs/cpu: Add probe/release files
powerpc/pseries: Kernel DLPAR Infrastructure
...
* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (189 commits)
drm/radeon/kms: fix warning about cur_placement being uninitialised.
drm/ttm: Print debug information on memory manager when eviction fails
drm: Add memory manager debug function
drm/radeon/kms: restore surface registers on resume.
drm/radeon/kms/r600/r700: fallback gracefully on ucode failure
drm/ttm: Initialize eviction placement in case the driver callback doesn't
drm/radeon/kms: cleanup structure and module if initialization fails
drm/radeon/kms: actualy set the eviction placements we choose
drm/radeon/kms: Fix NULL ptr dereference
drm/radeon/kms/avivo: add support for new pll selection algo
drm/radeon/kms/avivo: fix some bugs in the display bandwidth setup
drm/radeon/kms: fix return value from fence function.
drm/radeon: Remove tests for -ERESTART from the TTM code.
drm/ttm: Have the TTM code return -ERESTARTSYS instead of -ERESTART.
drm/radeon/kms: Convert radeon to new TTM validation API (V2)
drm/ttm: Rework validation & memory space allocation (V3)
drm: Add search/get functions to get a block in a specific range
drm/radeon/kms: fix avivo tiling regression since radeon object rework
drm/i915: Remove a debugging printk from hangcheck
drm/radeon/kms: make sure i2c id matches
...
* 'bkl-drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
agp: Remove the BKL from agp_open
inifiband: Remove BKL from ipath_open()
mips: Remove BKL from tb0219
drivers: Remove BKL from scx200_gpio
drivers: Remove BKL from pc8736x_gpio
parisc: Remove BKL from eisa_eeprom
rtc: Remove BKL from efirtc
input: Remove BKL from hp_sdc_rtc
hw_random: Remove BKL from core
macintosh: Remove BKL from ans-lcd
nvram: Drop the bkl from non-generic nvram_llseek()
nvram: Drop the bkl from nvram_llseek()
mem_class: Drop the bkl from memory_open()
spi: Remove BKL from spidev_open
drivers: Remove BKL from cs5535_gpio
drivers: Remove BKL from misc_open
This merges the upstream Intel tree and fixes up numerous conflicts
due to patches merged into Linus tree later in -rc cycle.
Conflicts:
drivers/char/agp/intel-agp.c
drivers/gpu/drm/drm_dp_i2c_helper.c
drivers/gpu/drm/i915/i915_irq.c
drivers/gpu/drm/i915/i915_suspend.c
Some BIOSes fail to initialise the GTT, which will cause DMA faults when
the IOMMU is enabled. We need to clear the whole thing to point at the
scratch page, not just the part that Linux is going to use.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
[anholt: Note that this may also help with stability in the presence of
driver bugs, by not drawing to memory we don't own]
Signed-off-by: Eric Anholt <eric@anholt.net>
IGD* isn't a useful name. Replace with the codenames, as sourced
from pci.ids.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
x86, Calgary IOMMU quirk: Find nearest matching Calgary while walking up the PCI tree
x86/amd-iommu: Remove amd_iommu_pd_table
x86/amd-iommu: Move reset_iommu_command_buffer out of locked code
x86/amd-iommu: Cleanup DTE flushing code
x86/amd-iommu: Introduce iommu_flush_device() function
x86/amd-iommu: Cleanup attach/detach_device code
x86/amd-iommu: Keep devices per domain in a list
x86/amd-iommu: Add device bind reference counting
x86/amd-iommu: Use dev->arch->iommu to store iommu related information
x86/amd-iommu: Remove support for domain sharing
x86/amd-iommu: Rearrange dma_ops related functions
x86/amd-iommu: Move some pte allocation functions in the right section
x86/amd-iommu: Remove iommu parameter from dma_ops_domain_alloc
x86/amd-iommu: Use get_device_id and check_device where appropriate
x86/amd-iommu: Move find_protection_domain to helper functions
x86/amd-iommu: Simplify get_device_resources()
x86/amd-iommu: Let domain_for_device handle aliases
x86/amd-iommu: Remove iommu specific handling from dma_ops path
x86/amd-iommu: Remove iommu parameter from __(un)map_single
x86/amd-iommu: Make alloc_new_range aware of multiple IOMMUs
...
We should set this before calling agp_add_bridge() so that it's done
before we map the scratch page too.
This should probably fix the regression reported as k.o. bug #14627.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add new CPU host bridge id, needed for support Ironlake graphics
device with it. No change for graphics device itself, so no need to
update drm/i915.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
The GART IOMMU code has no strong dependency to the AMD64
AGP code. So the automatic selection of AGP_AMD64 for GART
can be removed.
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Pavel Vasilyev <pavel@pavlinux.ru>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
- Remove the BKL from agp_open
- Perform a few clean-ups.
Analysis:
---------
int minor is local to the function.
The following are protected by agp_fe.agp_mutex
struct agp_file_private *priv;
struct agp_client *client;
Call-outs:
kzalloc should be safe to call under the mutex_lock
agp_find_client_by_pid:
- agp_mmap calls that under agp_fe.agp_mutex which we hold in agp_open
- agpioc_reserve_wrap calls it without any locking what-so-ever.
- Is that an error? Or is that okay because it has pid that is
a unique handle?
agp_insert_file_private:
- This function only manipulates struct agp_file_private, once again
while agp_fe.agp_mutex is held
Signed-off-by: John Kacur <jkacur@redhat.com>
Acked-by: David Airlie <airlied@linux.ie>
LKML-Reference: <alpine.LFD.2.00.0910112216060.12574@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code
But leave TTM code alone, something is fishy there with global vm_ops
being used.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel: (57 commits)
drm/i915: Handle ERESTARTSYS during page fault
drm/i915: Warn before mmaping a purgeable buffer.
drm/i915: Track purged state.
drm/i915: Remove eviction debug spam
drm/i915: Immediately discard any backing storage for uneeded objects
drm/i915: Do not mis-classify clean objects as purgeable
drm/i915: Whitespace correction for madv
drm/i915: BUG_ON page refleak during unbind
drm/i915: Search harder for a reusable object
drm/i915: Clean up evict from list.
drm/i915: Add tracepoints
drm/i915: framebuffer compression for GM45+
drm/i915: split display functions by chip type
drm/i915: Skip the sanity checks if the current relocation is valid
drm/i915: Check that the relocation points to within the target
drm/i915: correct FBC update when pipe base update occurs
drm/i915: blacklist Acer AspireOne lid status
ACPI: make ACPI button funcs no-ops if not built in
drm/i915: prevent FIFO calculation overflows on 32 bits with high dotclocks
drm/i915: intel_display.c handle latency variable efficiently
...
Fix up trivial conflicts in drivers/gpu/drm/i915/{i915_dma.c|i915_drv.h}
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (119 commits)
ACPI: don't pass handle for fixed hardware notifications
ACPI: remove null pointer checks in deferred execution path
ACPI: simplify deferred execution path
acerhdf: additional BIOS versions
acerhdf: convert to dev_pm_ops
acerhdf: fix fan control for AOA150 model
thermal: add missing Kconfig dependency
acpi: switch /proc/acpi/{debug_layer,debug_level} to seq_file
hp-wmi: fix rfkill memory leak on unload
ACPI: remove unnecessary #ifdef CONFIG_DMI
ACPI: linux/acpi.h should not include linux/dmi.h
hwmon driver for ACPI 4.0 power meters
topstar-laptop: add new driver for hotkeys support on Topstar N01
thinkpad_acpi: fix rfkill memory leak on unload
thinkpad-acpi: report brightness events when required
thinkpad-acpi: don't poll by default any of the reserved hotkeys
thinkpad-acpi: Fix procfs hotkey reset command
thinkpad-acpi: deprecate hotkey_bios_mask
thinkpad-acpi: hotkey poll fixes
thinkpad-acpi: be more strict when detecting a ThinkPad
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
trivial: fix typo in aic7xxx comment
trivial: fix comment typo in drivers/ata/pata_hpt37x.c
trivial: typo in kernel-parameters.txt
trivial: fix typo in tracing documentation
trivial: add __init/__exit macros in drivers/gpio/bt8xxgpio.c
trivial: add __init macro/ fix of __exit macro location in ipmi_poweroff.c
trivial: remove unnecessary semicolons
trivial: Fix duplicated word "options" in comment
trivial: kbuild: remove extraneous blank line after declaration of usage()
trivial: improve help text for mm debug config options
trivial: doc: hpfall: accept disk device to unload as argument
trivial: doc: hpfall: reduce risk that hpfall can do harm
trivial: SubmittingPatches: Fix reference to renumbered step
trivial: fix typos "man[ae]g?ment" -> "management"
trivial: media/video/cx88: add __init/__exit macros to cx88 drivers
trivial: fix typo in CONFIG_DEBUG_FS in gcov doc
trivial: fix missing printk space in amd_k7_smp_check
trivial: fix typo s/ketymap/keymap/ in comment
trivial: fix typo "to to" in multiple files
trivial: fix typos in comments s/DGBU/DBGU/
...
Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages. The amount of what actually is usable as storage
should instead be used as a basis here.
Some of the calculations (i.e. those not intending to use high memory)
should likely even use (totalram_pages - totalhigh_pages).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (134 commits)
powerpc/nvram: Enable use Generic NVRAM driver for different size chips
powerpc/iseries: Fix oops reading from /proc/iSeries/mf/*/cmdline
powerpc/ps3: Workaround for flash memory I/O error
powerpc/booke: Don't set DABR on 64-bit BookE, use DAC1 instead
powerpc/perf_counters: Reduce stack usage of power_check_constraints
powerpc: Fix bug where perf_counters breaks oprofile
powerpc/85xx: Fix SMP compile error and allow NULL for smp_ops
powerpc/irq: Improve nanodoc
powerpc: Fix some late PowerMac G5 with PCIe ATI graphics
powerpc/fsl-booke: Use HW PTE format if CONFIG_PTE_64BIT
powerpc/book3e: Add missing page sizes
powerpc/pseries: Fix to handle slb resize across migration
powerpc/powermac: Thermal control turns system off too eagerly
powerpc/pci: Merge ppc32 and ppc64 versions of phb_scan()
powerpc/405ex: support cuImage via included dtb
powerpc/405ex: provide necessary fixup function to support cuImage
powerpc/40x: Add support for the ESTeem 195E (PPC405EP) SBC
powerpc/44x: Add Eiger AMCC (AppliedMicro) PPC460SX evaluation board support.
powerpc/44x: Update Arches defconfig
powerpc/44x: Update Arches dts
...
Fix up conflicts in drivers/char/agp/uninorth-agp.c
* 'agp-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/agp-2.6:
agp/intel: remove restore in resume
agp: fix uninorth build
intel-agp: Set dma mask for i915
agp: kill phys_to_gart() and gart_to_phys()
intel-agp: fix sglist allocation to avoid vmalloc()
intel-agp: Move repeated sglist free into separate function
agp: Switch agp_{un,}map_page() to take struct page * argument
agp: tidy up handling of scratch pages w.r.t. DMA API
intel_agp: Use PCI DMA API correctly on chipsets new enough to have IOMMU
agp: Add generic support for graphics dma remapping
agp: Switch mask_memory() method to take address argument again, not page
As early pci resume has already restored config for host
bridge and graphics device, don't need to restore it again,
This removes an original order hack for graphics device restore.
This fixed the resume hang issue found by Alan Stern on 845G,
caused by extra config restore on graphics device.
Cc: Stable Team <stable@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Ever since we enabled GEM, the pre-9xx chipsets (particularly 865) have had
serious stability issues. Back in May a wbinvd was added to the DRM to
work around much of the problem. Some failure remained -- easily visible
by dragging a window around on an X -retro desktop, or by looking at bugzilla.
The chipset flush was on the right track -- hitting the right amount of
memory, and it appears to be the only way to flush on these chipsets, but the
flush page was mapped uncached. As a result, the writes trying to clear the
writeback cache ended up bypassing the cache, and not flushing anything! The
wbinvd would flush out other writeback data and often cause the data we wanted
to get flushed, but not always. By removing the setting of the page to UC
and instead just clflushing the data we write to try to flush it, we get the
desired behavior with no wbinvd.
This exports clflush_cache_range(), which was laying around and happened to
basically match the code I was otherwise going to copy from the DRM.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Cc: stable@kernel.org
New variant of IGDNG mobile chip has new host bridge id.
[anholt: Note that this new PCI ID doesn't impact the DRM, which doesn't
care about the PCI ID of the bridge]
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Completed a major update for the acpi_get_object_info external interface.
Changes include:
- Support for variable, unlimited length HID, UID, and CID strings
- Support Processor objects the same as Devices (HID,UID,CID,ADR,STA, etc.)
- Call the _SxW power methods on behalf of a device object
- Determine if a device is a PCI root bridge
- Change the ACPI_BUFFER parameter to ACPI_DEVICE_INFO.
These changes will require an update to all callers of this interface.
See the ACPICA Programmer Reference for details.
Also, update all invocations of acpi_get_object_info interface
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Map the GART table uncached, so we don't always need to flush the CPU caches
explicitly after updates.
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Using the radeon KMS test functionality, I verified that the AGP bridge of the
Intrepid2 chipset in my PowerBook supports aperture sizes up to 256M. So allow
aperture sizes up to 256M on pre-U3 bridges as well, and bump the default size
to 256M. It's possible that older revisions only support smaller sizes, but
it'll be easy to verify that with the raden KMS test functionality. Also,
there's only a problem on an actual attempt to access the aperture beyond the
maximum size supported by the hardware, and non-KMS X still defaults to using
only 32M.
Also use ARRAY_SIZE for the aperture size arrays.
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If DMAR is configured in but absent, we really do want to make sure that
the dma mask is set appropriately. Otherwise we get mapping failures on
highmem. Spotted by Zhenyu Wang.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
