<feed xmlns='http://www.w3.org/2005/Atom'>
<title>litmus-rt.git/drivers/pci/hotplug, branch linux-tip</title>
<subtitle>The LITMUS^RT kernel.</subtitle>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/'/>
<entry>
<title>PCI hotplug: ibmphp: Add check to prevent reading beyond mapped area</title>
<updated>2010-11-11T17:34:31+00:00</updated>
<author>
<name>Steven Rostedt</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2010-11-09T04:20:27+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=ac3abf2c37a9b0be604ea9825705a8510a9a6ba3'/>
<id>ac3abf2c37a9b0be604ea9825705a8510a9a6ba3</id>
<content type='text'>
While testing various randconfigs with ktest.pl, I hit the following panic:

BUG: unable to handle kernel paging request at f7e54b03
IP: [&lt;c0d63409&gt;] ibmphp_access_ebda+0x101/0x19bb

Adding printks, I found that the loop that reads the ebda blocks
can move out of the mapped section.

ibmphp_access_ebda: start=f7e44c00 size=5120 end=f7e46000
ibmphp_access_ebda: io_mem=f7e44d80 offset=384
ibmphp_access_ebda: io_mem=f7e54b03 offset=65283

The start of the iomap was at f7e44c00 and had a size of 5120,
making the end f7e46000. We start with an offset of 0x180 or
384, giving the first read at 0xf7e44d80. Reading that location
yields 65283, which is much bigger than the 5120 that was allocated
and makes the next read at f7e54b03 which is outside the mapped area.

Perhaps this is a bug in the driver, or buggy hardware, but this patch
is more about not crashing my box on start up and just giving a warning
if it detects this error.

This patch at least lets my box boot with just a warning.

Cc: Chandru Siddalingappa &lt;chandru@linux.vnet.ibm.com&gt;
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
While testing various randconfigs with ktest.pl, I hit the following panic:

BUG: unable to handle kernel paging request at f7e54b03
IP: [&lt;c0d63409&gt;] ibmphp_access_ebda+0x101/0x19bb

Adding printks, I found that the loop that reads the ebda blocks
can move out of the mapped section.

ibmphp_access_ebda: start=f7e44c00 size=5120 end=f7e46000
ibmphp_access_ebda: io_mem=f7e44d80 offset=384
ibmphp_access_ebda: io_mem=f7e54b03 offset=65283

The start of the iomap was at f7e44c00 and had a size of 5120,
making the end f7e46000. We start with an offset of 0x180 or
384, giving the first read at 0xf7e44d80. Reading that location
yields 65283, which is much bigger than the 5120 that was allocated
and makes the next read at f7e54b03 which is outside the mapped area.

Perhaps this is a bug in the driver, or buggy hardware, but this patch
is more about not crashing my box on start up and just giving a warning
if it detects this error.

This patch at least lets my box boot with just a warning.

Cc: Chandru Siddalingappa &lt;chandru@linux.vnet.ibm.com&gt;
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6</title>
<updated>2010-10-28T18:59:52+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2010-10-28T18:59:52+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=e9f29c9a56ca06d0effa557823a737cbe7ec09f7'/>
<id>e9f29c9a56ca06d0effa557823a737cbe7ec09f7</id>
<content type='text'>
* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (27 commits)
  x86: allocate space within a region top-down
  x86: update iomem_resource end based on CPU physical address capabilities
  x86/PCI: allocate space from the end of a region, not the beginning
  PCI: allocate bus resources from the top down
  resources: support allocating space within a region from the top down
  resources: handle overflow when aligning start of available area
  resources: ensure callback doesn't allocate outside available space
  resources: factor out resource_clip() to simplify find_resource()
  resources: add a default alignf to simplify find_resource()
  x86/PCI: MMCONFIG: fix region end calculation
  PCI: Add support for polling PME state on suspended legacy PCI devices
  PCI: Export some PCI PM functionality
  PCI: fix message typo
  PCI: log vendor/device ID always
  PCI: update Intel chipset names and defines
  PCI: use new ccflags variable in Makefile
  PCI: add PCI_MSIX_TABLE/PBA defines
  PCI: add PCI vendor id for STmicroelectronics
  x86/PCI: irq and pci_ids patch for Intel Patsburg DeviceIDs
  PCI: OLPC: Only enable PCI configuration type override on XO-1
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (27 commits)
  x86: allocate space within a region top-down
  x86: update iomem_resource end based on CPU physical address capabilities
  x86/PCI: allocate space from the end of a region, not the beginning
  PCI: allocate bus resources from the top down
  resources: support allocating space within a region from the top down
  resources: handle overflow when aligning start of available area
  resources: ensure callback doesn't allocate outside available space
  resources: factor out resource_clip() to simplify find_resource()
  resources: add a default alignf to simplify find_resource()
  x86/PCI: MMCONFIG: fix region end calculation
  PCI: Add support for polling PME state on suspended legacy PCI devices
  PCI: Export some PCI PM functionality
  PCI: fix message typo
  PCI: log vendor/device ID always
  PCI: update Intel chipset names and defines
  PCI: use new ccflags variable in Makefile
  PCI: add PCI_MSIX_TABLE/PBA defines
  PCI: add PCI vendor id for STmicroelectronics
  x86/PCI: irq and pci_ids patch for Intel Patsburg DeviceIDs
  PCI: OLPC: Only enable PCI configuration type override on XO-1
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq</title>
<updated>2010-10-23T00:13:10+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2010-10-23T00:13:10+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=91b745016c12d440386c40fb76ab69c8e08cbc06'/>
<id>91b745016c12d440386c40fb76ab69c8e08cbc06</id>
<content type='text'>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: remove in_workqueue_context()
  workqueue: Clarify that schedule_on_each_cpu is synchronous
  memory_hotplug: drop spurious calls to flush_scheduled_work()
  shpchp: update workqueue usage
  pciehp: update workqueue usage
  isdn/eicon: don't call flush_scheduled_work() from diva_os_remove_soft_isr()
  workqueue: add and use WQ_MEM_RECLAIM flag
  workqueue: fix HIGHPRI handling in keep_working()
  workqueue: add queue_work and activate_work trace points
  workqueue: prepare for more tracepoints
  workqueue: implement flush[_delayed]_work_sync()
  workqueue: factor out start_flush_work()
  workqueue: cleanup flush/cancel functions
  workqueue: implement alloc_ordered_workqueue()

Fix up trivial conflict in fs/gfs2/main.c as per Tejun
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: remove in_workqueue_context()
  workqueue: Clarify that schedule_on_each_cpu is synchronous
  memory_hotplug: drop spurious calls to flush_scheduled_work()
  shpchp: update workqueue usage
  pciehp: update workqueue usage
  isdn/eicon: don't call flush_scheduled_work() from diva_os_remove_soft_isr()
  workqueue: add and use WQ_MEM_RECLAIM flag
  workqueue: fix HIGHPRI handling in keep_working()
  workqueue: add queue_work and activate_work trace points
  workqueue: prepare for more tracepoints
  workqueue: implement flush[_delayed]_work_sync()
  workqueue: factor out start_flush_work()
  workqueue: cleanup flush/cancel functions
  workqueue: implement alloc_ordered_workqueue()

Fix up trivial conflict in fs/gfs2/main.c as per Tejun
</pre>
</div>
</content>
</entry>
<entry>
<title>shpchp: update workqueue usage</title>
<updated>2010-10-18T06:33:02+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2010-10-18T06:33:02+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=e24dcbef93dbbf529fbedfc6ce8ab22d2cef35f0'/>
<id>e24dcbef93dbbf529fbedfc6ce8ab22d2cef35f0</id>
<content type='text'>
* Rename shpchp_wq to shpchp_ordered_wq and add non-ordered shpchp_wq
  which is used instead of the system workqueue.  This is to remove
  the use of flush_scheduled_work() which is deprecated and scheduled
  for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
  Create both shpchp_wq and shpchp_ordered_wq upfront.

* Include workqueue.h from shpchp.h.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* Rename shpchp_wq to shpchp_ordered_wq and add non-ordered shpchp_wq
  which is used instead of the system workqueue.  This is to remove
  the use of flush_scheduled_work() which is deprecated and scheduled
  for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
  Create both shpchp_wq and shpchp_ordered_wq upfront.

* Include workqueue.h from shpchp.h.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pciehp: update workqueue usage</title>
<updated>2010-10-18T06:31:02+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2010-10-18T06:31:02+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=a827ea307b147aeb050803433b3f6842582c6ced'/>
<id>a827ea307b147aeb050803433b3f6842582c6ced</id>
<content type='text'>
* Rename pciehp_wq to pciehp_ordered_wq and add non-ordered pciehp_wq
  which is used instead of the system workqueue.  This is to remove
  the use of flush_scheduled_work() which is deprecated and scheduled
  for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
  Create both pciehp_wq and pciehp_ordered_wq upfront.

* Include workqueue.h from pciehp.h.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* Rename pciehp_wq to pciehp_ordered_wq and add non-ordered pciehp_wq
  which is used instead of the system workqueue.  This is to remove
  the use of flush_scheduled_work() which is deprecated and scheduled
  for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
  Create both pciehp_wq and pciehp_ordered_wq upfront.

* Include workqueue.h from pciehp.h.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI hotplug: ibmphp-hpc: semaphore cleanup</title>
<updated>2010-10-15T20:09:48+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2010-09-07T14:32:38+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=5a37f1381f1d8625fa458360c9b5d17f0c5f1dea'/>
<id>5a37f1381f1d8625fa458360c9b5d17f0c5f1dea</id>
<content type='text'>
Get rid of init_MUTEX[_LOCKED]() and use sema_init() instead.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Get rid of init_MUTEX[_LOCKED]() and use sema_init() instead.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers: autoconvert trivial BKL users to private mutex</title>
<updated>2010-10-05T13:01:04+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2010-06-02T12:28:52+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=613655fa39ff6957754fa8ceb8559980920eb8ee'/>
<id>613655fa39ff6957754fa8ceb8559980920eb8ee</id>
<content type='text'>
All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*&lt;linux\/smp_lock.h&gt;/d' ${file}
    else
            sed -i 's/include.*&lt;linux\/smp_lock.h&gt;.*$/include &lt;linux\/mutex.h&gt;/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\&gt;[ ]*()/mutex_\1lock(\&amp;${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\&lt;smp_lock.h\&gt;/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*&lt;linux\/smp_lock.h&gt;/d' ${file}
    else
            sed -i 's/include.*&lt;linux\/smp_lock.h&gt;.*$/include &lt;linux\/mutex.h&gt;/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\&gt;[ ]*()/mutex_\1lock(\&amp;${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\&lt;smp_lock.h\&gt;/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI hotplug: Fix build with CONFIG_ACPI unset</title>
<updated>2010-08-25T19:54:03+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2010-08-25T19:33:29+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=6e63e80d88521a176989ed14b420f42dc418e46a'/>
<id>6e63e80d88521a176989ed14b420f42dc418e46a</id>
<content type='text'>
One of the recent changes caused complilation of
drivers/pci/hotplug/pciehp_core.c to fail.  Fix this issue.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
One of the recent changes caused complilation of
drivers/pci/hotplug/pciehp_core.c to fail.  Fix this issue.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: PCIe: Ask BIOS for control of all native services at once</title>
<updated>2010-08-24T20:47:33+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2010-08-21T20:02:38+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=28eb5f274a305bf3a13b2c80c4804d4515d05c64'/>
<id>28eb5f274a305bf3a13b2c80c4804d4515d05c64</id>
<content type='text'>
After commit 852972acff8f10f3a15679be2059bb94916cba5d (ACPI: Disable
ASPM if the platform won't provide _OSC control for PCIe) control of
the PCIe Capability Structure is unconditionally requested by
acpi_pci_root_add(), which in principle may cause problems to
happen in two ways.  First, the BIOS may refuse to give control of
the PCIe Capability Structure if it is not asked for any of the
_OSC features depending on it at the same time.  Second, the BIOS may
assume that control of the _OSC features depending on the PCIe
Capability Structure will be requested in the future and may behave
incorrectly if that doesn't happen.  For this reason, control of
the PCIe Capability Structure should always be requested along with
control of any other _OSC features that may depend on it (ie. PCIe
native PME, PCIe native hot-plug, PCIe AER).

Rework the PCIe port driver so that (1) it checks which native PCIe
port services can be enabled, according to the BIOS, and (2) it
requests control of all these services simultaneously.  In
particular, this causes pcie_portdrv_probe() to fail if the BIOS
refuses to grant control of the PCIe Capability Structure, which
means that no native PCIe port services can be enabled for the PCIe
Root Complex the given port belongs to.  If that happens, ASPM is
disabled to avoid problems with mishandling it by the part of the
PCIe hierarchy for which control of the PCIe Capability Structure
has not been received.

Make it possible to override this behavior using 'pcie_ports=native'
(use the PCIe native services regardless of the BIOS response to the
control request), or 'pcie_ports=compat' (do not use the PCIe native
services at all).

Accordingly, rework the existing PCIe port service drivers so that
they don't request control of the services directly.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After commit 852972acff8f10f3a15679be2059bb94916cba5d (ACPI: Disable
ASPM if the platform won't provide _OSC control for PCIe) control of
the PCIe Capability Structure is unconditionally requested by
acpi_pci_root_add(), which in principle may cause problems to
happen in two ways.  First, the BIOS may refuse to give control of
the PCIe Capability Structure if it is not asked for any of the
_OSC features depending on it at the same time.  Second, the BIOS may
assume that control of the _OSC features depending on the PCIe
Capability Structure will be requested in the future and may behave
incorrectly if that doesn't happen.  For this reason, control of
the PCIe Capability Structure should always be requested along with
control of any other _OSC features that may depend on it (ie. PCIe
native PME, PCIe native hot-plug, PCIe AER).

Rework the PCIe port driver so that (1) it checks which native PCIe
port services can be enabled, according to the BIOS, and (2) it
requests control of all these services simultaneously.  In
particular, this causes pcie_portdrv_probe() to fail if the BIOS
refuses to grant control of the PCIe Capability Structure, which
means that no native PCIe port services can be enabled for the PCIe
Root Complex the given port belongs to.  If that happens, ASPM is
disabled to avoid problems with mishandling it by the part of the
PCIe hierarchy for which control of the PCIe Capability Structure
has not been received.

Make it possible to override this behavior using 'pcie_ports=native'
(use the PCIe native services regardless of the BIOS response to the
control request), or 'pcie_ports=compat' (do not use the PCIe native
services at all).

Accordingly, rework the existing PCIe port service drivers so that
they don't request control of the services directly.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI/PCI: Negotiate _OSC control bits before requesting them </title>
<updated>2010-08-24T20:44:40+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2010-08-23T21:53:11+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=75fb60f26befb59dbfa05cb122972642b7bdd219'/>
<id>75fb60f26befb59dbfa05cb122972642b7bdd219</id>
<content type='text'>
It is possible that the BIOS will not grant control of all _OSC
features requested via acpi_pci_osc_control_set(), so it is
recommended to negotiate the final set of _OSC features with the
query flag set before calling _OSC to request control of these
features.

To implement it, rework acpi_pci_osc_control_set() so that the caller
can specify the mask of _OSC control bits to negotiate and the mask
of _OSC control bits that are absolutely necessary to it.  Then,
acpi_pci_osc_control_set() will run _OSC queries in a loop until
the mask of _OSC control bits returned by the BIOS is equal to the
mask passed to it.  Also, before running the _OSC request
acpi_pci_osc_control_set() will check if the caller's required
control bits are present in the final mask.

Using this mechanism we will be able to avoid situations in which the
BIOS doesn't grant control of certain _OSC features, because they
depend on some other _OSC features that have not been requested.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
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<pre>
It is possible that the BIOS will not grant control of all _OSC
features requested via acpi_pci_osc_control_set(), so it is
recommended to negotiate the final set of _OSC features with the
query flag set before calling _OSC to request control of these
features.

To implement it, rework acpi_pci_osc_control_set() so that the caller
can specify the mask of _OSC control bits to negotiate and the mask
of _OSC control bits that are absolutely necessary to it.  Then,
acpi_pci_osc_control_set() will run _OSC queries in a loop until
the mask of _OSC control bits returned by the BIOS is equal to the
mask passed to it.  Also, before running the _OSC request
acpi_pci_osc_control_set() will check if the caller's required
control bits are present in the final mask.

Using this mechanism we will be able to avoid situations in which the
BIOS doesn't grant control of certain _OSC features, because they
depend on some other _OSC features that have not been requested.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
</pre>
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</content>
</entry>
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