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authorDavid Woodhouse <David.Woodhouse@intel.com>2008-09-01 11:32:13 +0100
committerDavid Woodhouse <David.Woodhouse@intel.com>2008-09-01 11:32:13 +0100
commit9d7548d4ca3c52ecb58f098a32b0756cdf8f96ee (patch)
tree651f7058bbaa2d8b2855286380d614afcf505118 /Documentation/usb/power-management.txt
parent31db6e9ea1dbdcf66b8227b4f7035dee1b1dd8c0 (diff)
parentbef69ea0dcce574a425feb0a5aa4c63dd108b9a6 (diff)
downloadtalos-obmc-linux-9d7548d4ca3c52ecb58f098a32b0756cdf8f96ee.tar.gz
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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'Documentation/usb/power-management.txt')
-rw-r--r--Documentation/usb/power-management.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index b2fc4d4a9917..9d31140e3f5b 100644
--- a/Documentation/usb/power-management.txt
+++ b/Documentation/usb/power-management.txt
@@ -436,7 +436,12 @@ post_reset; the USB core guarantees that this is true of internal
suspend/resume events as well.
If a driver wants to block all suspend/resume calls during some
-critical section, it can simply acquire udev->pm_mutex.
+critical section, it can simply acquire udev->pm_mutex. Note that
+calls to resume may be triggered indirectly. Block IO due to memory
+allocations can make the vm subsystem resume a device. Thus while
+holding this lock you must not allocate memory with GFP_KERNEL or
+GFP_NOFS.
+
Alternatively, if the critical section might call some of the
usb_autopm_* routines, the driver can avoid deadlock by doing:
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