Change for PCI hotplug to use pci_is_pcie() instead of checking
pci_dev->is_pcie.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Changes for PCIe AER driver to use pci_is_pcie() instead of checking
pci_dev->is_pcie.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Change for PCIe ASPM driver to use pci_is_pcie() instead of checking
pci_dev->is_pcie.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Change for PCI core to use pci_is_pcie() instead of checking
pci_dev->is_pcie.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Introduce pci_is_pcie() which returns true if the specified PCI device
is PCI Express capable, false otherwise.
The purpose of pci_is_pcie() is removing 'is_pcie' flag in the struct
pci_dev, which is not needed because we can check it using 'pcie_cap'
field. To remove 'is_pcie', we need to update user of 'is_pcie' to use
pci_is_pcie() instead first.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pci_pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in pciehp driver. This avoids unnecessary search in PCI
configuration space. This patch also removes 'cap_base' field in
struct controller, that was used to hold PCIe capability offset by
pciehp itself.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pci_pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCI hotplug core. This avoids unnecessary search in PCI
configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pci_pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCIe ASPM driver. This avoids unnecessary search in PCI
configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pci_pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCI Express Port Bus driver. This avoids unnecessary serarch
in PCI configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCIe AER driver. This avoids unnecessary search in PCI
configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use pcie_cap() instead of pci_find_capability() to get PCIe capability
offset in PCI core code. This avoids unnecessary search in PCI
configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Introduce pci_pcie_cap() API that returns saved PCIe capability offset
(currently it is saved in 'pcie_cap' field in the struct PCI dev).
Using pci_pcie_cap() instead of pci_find_capability() avoids
unnecessary search in PCI configuration space.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
I'm not entirely sure it needs to go into 32, but it's probably the right
thing to do. Another way of explaining the patch is:
- we currently pick the _first_ exactly matching bus resource entry, but
the _last_ inexactly matching one. Normally first/last shouldn't
matter, but bus resource entries aren't actually all created equal: in
a transparent bus, the last resources will be the parent resources,
which we should generally try to avoid unless we have no choice. So
"first matching" is the thing we should always aim for.
- the patch is a bit bigger than it needs to be, because I simplified the
logic at the same time. It used to be a fairly incomprehensible
if ((res->flags & IORESOURCE_PREFETCH) && !(r->flags & IORESOURCE_PREFETCH))
best = r; /* Approximating prefetchable by non-prefetchable */
and technically, all the patch did was to make that complex choice be
even more complex (it basically added a "&& !best" to say that if we
already gound a non-prefetchable window for the prefetchable resource,
then we won't override an earlier one with that later one: remember
"first matching").
- So instead of that complex one with three separate conditionals in one,
I split it up a bit, and am taking advantage of the fact that we
already handled the exact case, so if 'res->flags' has the PREFETCH
bit, then we already know that 'r->flags' will _not_ have it. So the
simplified code drops the redundant test, and does the new '!best' test
separately. It also uses 'continue' as a way to ignore the bus
resource we know doesn't work (ie a prefetchable bus resource is _not_
acceptable for anything but an exact match), so it turns into:
/* We can't insert a non-prefetch resource inside a prefetchable parent .. */
if (r->flags & IORESOURCE_PREFETCH)
continue;
/* .. but we can put a prefetchable resource inside a non-prefetchable one */
if (!best)
best = r;
instead. With the comments, it's now six lines instead of two, but it's
conceptually simpler, and I _could_ have written it as two lines:
if ((res->flags & IORESOURCE_PREFETCH) && !best)
best = r; /* Approximating prefetchable by non-prefetchable */
but I thought that was too damn subtle.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
SPIN_LOCK_UNLOCKED is deprecated. Use DEFINE_SPINLOCK instead.
Make the lock static while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch fixes the following compilation error introduced by a PCI related
features.
The change set of 5dd1af9f84c79bedd589db89e71ca733f3bf0ebd moves some
xen related definitions from the arch header file
(x86/include/asm/xen/hypervisor.h) to the common header file
(include/xen/xen.h). So ia64/xen also follows it.
In file included from linux-next/include/xen/grant_table.h:41,
from linux-next/drivers/block/xen-blkfront.c:48:
linux-next/arch/ia64/include/asm/xen/hypervisor.h:43: error: nested redefinition of 'enum xen_domain_type'
linux-next/arch/ia64/include/asm/xen/hypervisor.h:43: error: redeclaration of 'enum xen_domain_type'
linux-next/arch/ia64/include/asm/xen/hypervisor.h:44: error: redeclaration of enumerator 'XEN_NATIVE'
linux-next/include/xen/xen.h:5: error: previous definition of 'XEN_NATIVE' was here
linux-next/arch/ia64/include/asm/xen/hypervisor.h:45: error: redeclaration of enumerator 'XEN_PV_DOMAIN'
linux-next/include/xen/xen.h:6: error: previous definition of 'XEN_PV_DOMAIN' was here
linux-next/arch/ia64/include/asm/xen/hypervisor.h:46: error: redeclaration of enumerator 'XEN_HVM_DOMAIN'
linux-next/include/xen/xen.h:7: error: previous definition of 'XEN_HVM_DOMAIN' was here
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
If firmware doesn't grant over native hotplug control through ACPI
_OSC method, we must not evaluate OSHP.
Acked-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
In case of AMD CPU northbridge functions this NUMA information might
differ. Here is an example from a 4-socket system.
Currently Linux shows
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
0
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat local_cpu*
0-3
00000000,0000000f
which is not correct for northbridge functions as the local CPUs
are those of the same socket.
With this patch and a quirk for AMD CPU NB functions Linux can
do better and correctly show
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
2
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat local_cpu*
8-11
00000000,00000f00
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The roundup() caused a build error (undefined reference to `__udivdi3').
We're aligning to power-of-two boundaries, so it's simpler to just use
ALIGN() anyway, which avoids the division.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
There are a lot of codes that searches PCI express capability offset
in the PCI configuration space using pci_find_capability(). Caching it
in the struct pci_dev will reduce unncecessary search. This patch adds
an additional 'pcie_cap' fields into struct pci_dev, which is
initialized at pci device scan time (in set_pcie_port_type()).
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
When "allocate_resource(root, new, size, ...)" fails, we currently
clobber "new". This is inconvenient for the caller, who might care
about the original contents of the resource.
For example, when pci_bus_alloc_resource() fails, the "can't allocate
mem resource %pR" message from pci_assign_resources() currently contains
junk for the resource start/end.
This patch delays the "new" update until we're about to return success.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
PCI device BARs are guaranteed to start and end on at least a four-byte
(I/O) or a sixteen-byte (MMIO) boundary because they're aligned on their
size and the low BAR bits are reserved. PCI-to-PCI bridge apertures
have even larger alignment restrictions.
However, some BIOSes (e.g., HP DL360 BIOS P31) report host bridge windows
like "[io 0x0000-0x2cfe]". This is wrong because it excludes the last
port at 0x2cff: it's impossible for a downstream device to claim 0x2cfe
without also claiming 0x2cff. In fact, this BIOS configures a device
behind the bridge to "[io 0x2c00-0x2cff]", so we know the window actually
does include 0x2cff.
This patch rounds the start and end of apertures to the appropriate
boundary. I experimentally determined that Windows contains a similar
workaround; details here:
http://bugzilla.kernel.org/show_bug.cgi?id=14337
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
We have occasional problems with PCI resource allocation, and sometimes
they could be avoided by paying attention to what ACPI tells us about
the host bridges. This patch doesn't change the behavior, but it prints
window information that should make debugging easier.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This makes PCI resource management messages more consistent and adds a few
new messages to aid debugging.
Whenever we assign resources to a device, update a BAR, or change a
bridge aperture, it's worth noting it.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Since we have a struct device, we might as well use dev_printk. Note that
both pr_debug() and dev_dbg() are completely compiled out unless DEBUG or
DYNAMIC_DEBUG is defined.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Use the dev_printk-like "%04x:%02x" format for printing PCI bus numbers.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Messages about PME# being supported and enabled/disabled are probably
useful for debug, but maybe don't need to be on the console.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Commit 3b073eda has removed pci_find_slot, so there's no point in
mentioning it in the config description as one of the deprecated APIs
there are enabled by PCI_LEGACY and still used by some drivers.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Jesse accidentally applied v1 [1] of the patchset instead of v2 [2]. This
is the diff between v1 and v2.
The changes in this patch are:
- tidied vsprintf stack buffer to shrink and compute size more
accurately
- use %pR for decoding and %pr for "raw" (with type and flags) instead
of adding %pRt and %pRf
[1] http://lkml.org/lkml/2009/10/6/491
[2] http://lkml.org/lkml/2009/10/13/441
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
AMD 813x rev. B1 (like rev. B2) devices generate no interrupts if
quirk_disable_amd_813x_boot_interrupt is executed, add an exception.
http://bugzilla.kernel.org/show_bug.cgi?id=14159
Patch also adds missing cases for DECLARE_PCI_FIXUP_RESUME and
DECLARE_PCI_FIXUP_FINAL calls to quirk_disable_amd_813x_boot_interrupt.
Signed-off-by: Stefan Assmann <sassmann@redhat.com>
Tested-by: Gabriele Giorgetti <g.giorgetti@teamsystem.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Using list_for_each_entry instead of list_for_each allows us to
enhance readability and minorly reduce some stack usage.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch moves PCI I/O APIC support from acpiphp to a separate driver.
Like pciehp and shpchp, acpiphp handles PCI hotplug, i.e., addition and
removal of PCI adapters. But in addition, acpiphp handles some ACPI
hotplug, such as the addition of new host bridges, and the I/O APIC
support was tangled up with that.
I don't think the I/O APIC support needs to be in acpiphp; PCI I/O APICs
usually appear as a function on a PCI host bridge, and we'll enumerate the
APIC before any of the devices behind the bridge that use it.
As far as I know, nobody actually uses I/O APIC hotplug. It depends on
acpi_register_ioapic(), which is only implemented for ia64, and I don't
think any vendors have supported I/O chassis hotplug yet.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
CC: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
CC: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Replaced some error return values in aer_inject. Use -ENODEV when we
can't find a device and -ENOTTY when the device does not support PCIe AER.
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Add support for PCI domains (segments) to aer_inject.
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Added the pci_get_domain_and_slot_function which is analogous to
pci_get_bus_and_slot. It returns a pci_dev given a domain (segment) number,
bus number, and devnr. Like pci_get_bus_and_slot,
pci_get_domain_bus_and_slot holds a reference to the returned pci_dev.
Converted pci_get_bus_and_slot to a wrapper that calls
pci_get_domain_bus_and_slot with the domain hard-coded to 0.
This routine was patterned off code suggested by Bjorn Helgaas.
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Change to populate the subsystem vendor and subsytem device IDs for
PCI-PCI bridges that implement the PCI Subsystem Vendor ID capability.
Previously bridges left subsystem vendor IDs unpopulated.
Signed-off-by: Gabe Black <gabe.black@ni.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Feedback from Hidetoshi Seto and Kenji Kaneshige incorporated. This
correctly handles PCI-X bridges, PCIe root ports and endpoints, and
prints debug messages when invalid/reserved types are found in the
HEST. PCI devices not in domain/segment 0 are not represented in
HEST, thus will be ignored.
Today, the PCIe Advanced Error Reporting (AER) driver attaches itself
to every PCIe root port for which BIOS reports it should, via ACPI
_OSC.
However, _OSC alone is insufficient for newer BIOSes. Part of ACPI
4.0 is the new APEI (ACPI Platform Error Interfaces) which is a way
for OS and BIOS to handshake over which errors for which components
each will handle. One table in ACPI 4.0 is the Hardware Error Source
Table (HEST), where BIOS can define that errors for certain PCIe
devices (or all devices), should be handled by BIOS ("Firmware First
mode"), rather than be handled by the OS.
Dell PowerEdge 11G server BIOS defines Firmware First mode in HEST, so
that it may manage such errors, log them to the System Event Log, and
possibly take other actions. The aer driver should honor this, and
not attach itself to devices noted as such.
Furthermore, Kenji Kaneshige reminded us to disallow changing the AER
registers when respecting Firmware First mode. Platform firmware is
expected to manage these, and if changes to them are allowed, it could
break that firmware's behavior.
The HEST parsing code may be replaced in the future by a more
feature-rich implementation. This patch provides the minimum needed
to prevent breakage until that implementation is available.
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Prevent unnecessary power off at initialization time. If slot power
is already off, we don't need to power off the slot.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Current pciehp returns successfully on read/write failure with dummy
state values. It should return error instead.
With this patch, pciehp no longer uses hotplug_slot_info data
structure. So this also removes hotplug_slot_info related code. But
note that it still allocates hotplug_slot_info because it is required
by pci hotplug core.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Current pciehp driver creates 'attention' and 'latch' files even if
the controller doesn't support them. In this case, the contents of
those files are meaningless and unpredictable. Those files should be
created only if the controller has the corresponding capabilities.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Remove wrong workaround for BAD DLLP error, which confused surprise
down error with DLL errors.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Current pciehp doesn't handle Data Link Layer State Changed Event
notification. So it needs to be disabled at initialization time,
otherwise other event notifications are not generated.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
When probing for ROM BAR size, we should not change bits 1:10 in this
BAR, because these bits are marked as "reserved for future use" in PCI
spec, so changing them might have side effects.
No such issue for I/O or memory, as there is an implementation note in
PCI spec which explicitly allows writing 0xfffffffff there.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
We use dev_dbg() in arch/x86/pci, but there's no easy way to turn it
on. Add -DDEBUG when CONFIG_PCI_DEBUG=y, just like we do in drivers/pci.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This patch is predicated on Jeremy's patch in include/xen/xen.h. It'll
prevent ACS init unless the platform has both an IOMMU and we're running
as dom0.
Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Note: dom0 checking in v4 has been separated out into 2/2.
This patch enables P2P upstream forwarding in ACS capable PCIe switches.
It solves two potential problems in virtualization environment where a PCIe
device is assigned to a guest domain using a HW iommu such as VT-d:
1) Unintentional failure caused by guest physical address programmed
into the device's DMA that happens to match the memory address range
of other downstream ports in the same PCIe switch. This causes the PCI
transaction to go to the matching downstream port instead of go to the
root complex to get translated by VT-d as it should be.
2) Malicious guest software intentionally attacks another downstream
PCIe device by programming the DMA address into the assigned device
that matches memory address range of the downstream PCIe port.
We are in process of implementing device filtering software in KVM/XEN
management software to allow device assignment of PCIe devices behind a PCIe
switch only if it has ACS capability and with the P2P upstream forwarding bits
enabled. This patch is intended to work for both KVM and Xen environments.
Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Reviewed-by: Mathew Wilcox <willy@linux.intel.com>
Reviewed-by: Chris Wright <chris@sous-sol.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Move xen_domain and related tests out of asm-x86 to xen/xen.h so they
can be included whenever they are necessary.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The current whitelist requires a kernel change for every machine that has
MMCONFIG regions above 4GB, even if BIOS provides a correct MCFG table.
This patch expands the whitelist to include machines with a rev 1 or newer
MCFG table and a DMI_BIOS_DATE of 2010 or later. That way, we only need
kernel changes for new machines that provide incorrect MCFG tables.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
CC: Matthew Wilcox <willy@linux.intel.com>
CC: John Keller <jpk@sgi.com>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
CC: Andi Kleen <andi@firstfloor.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Thomas Schlichter reported:
> X.org uses libpciaccess which tries to mmap with write combining enabled via
> /sys/bus/pci/devices/*/resource0_wc. Currently, when PAT is not enabled, the
> kernel does fall back to uncached mmap. Then libpciaccess thinks it succeeded
> mapping with write combining enabled and does not set up suited MTRR entries.
> ;-(
Instead of silently mapping pci mmap region as UC minus in the case
of !pat_enabled and wc request, we can return error. Eric Anholt mentioned
that caller (like X) typically follows up with UC minus pci mmap request and
if there is a free mtrr slot, caller will manage adding WC mtrr.
Jesse Barnes says:
> Older versions of libpciaccess will behave better if we do it that way
> (iirc it only allocates an MTRR if the resource_wc file doesn't exist or
> fails to get mapped).
Reported-by: Thomas Schlichter <thomas.schlichter@web.de>
Signed-off-by: Thomas Schlichter <thomas.schlichter@web.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Kenji Kaneshige