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authorMing Lei <ming.lei@canonical.com>2013-03-15 12:08:53 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-25 10:55:46 -0700
commit303f0847925ece27129487a2bfc05199ab2a0b51 (patch)
treed368d2f9376bb452d9c79f466c710a5d7d38b64e /drivers/usb/core/driver.c
parent2849a3a945d0e440fa245c47c49c80ef1cc103c3 (diff)
USB: adds comment on suspend callback
This patch adds comments on interface driver suspend callback to emphasize that the failure return value is ignored by USB core in system sleep context, so do not try to recover device for this case and let resume/reset_resume callback handle the suspend failure if needed. Also kerneldoc for usb_suspend_both() is updated with the fact. Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/driver.c')
-rw-r--r--drivers/usb/core/driver.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index d938b2b99e31..eb1d00a3543a 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1196,9 +1196,14 @@ done:
*
* This is the central routine for suspending USB devices. It calls the
* suspend methods for all the interface drivers in @udev and then calls
- * the suspend method for @udev itself. If an error occurs at any stage,
- * all the interfaces which were suspended are resumed so that they remain
- * in the same state as the device.
+ * the suspend method for @udev itself. When the routine is called in
+ * autosuspend, if an error occurs at any stage, all the interfaces
+ * which were suspended are resumed so that they remain in the same
+ * state as the device, but when called from system sleep, all error
+ * from suspend methods of interfaces and the non-root-hub device itself
+ * are simply ignored, so all suspended interfaces are only resumed
+ * to the device's state when @udev is root-hub and its suspend method
+ * returns failure.
*
* Autosuspend requests originating from a child device or an interface
* driver may be made without the protection of @udev's device lock, but