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author | Jon Hunter <jon-hunter@ti.com> | 2009-08-12 15:57:59 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-09-23 13:46:33 (GMT) |
commit | 015798b2f166725b1dae2b07b5ffb127ab187be0 (patch) | |
tree | 8e737d2a85ba93bbe135051c426993f9cc272f2a /drivers/usb/host/isp1362-hcd.c | |
parent | 0ffd3b2902e28b13d8379df0f09a55668f330f77 (diff) | |
download | linux-015798b2f166725b1dae2b07b5ffb127ab187be0.tar.xz |
USB: EHCI: ensure all watchdog timer events are deleted when suspending usb
This patch was previously discussed in the following thread:
http://thread.gmane.org/gmane.linux.usb.general/19472/focus=19484
On the OMAP3 device the usbhost controller is in a separate internal
power-domain. So when the usbhost is inactive or suspend is called,
we can disable clocks and power-down the usbhost to save power.
Recently we found that after calling ehci_bus_suspend() and disabling
the usbhost clocks we would see the ehci watchdog timer event fire. This
was causing a kernel panic because the usbhost controllers clocks were
disabled and inside the watchdog timer function the clocks were not
being re-enabled, so when the ehci registers were accessed this resulted
in a CPU data-abort.
To avoid this panic, per recommendation from Alan Stern (see above thread), we
make sure any pending timer events (that may have been scheduled by calling
ehci_work within the ehci_bus_suspend() function) are deleted before returning.
Signed-off-by: Fei Yang <fei.yang@motorola.com>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/isp1362-hcd.c')
0 files changed, 0 insertions, 0 deletions