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USB: Prevent system suspend when HSIC device is active 

Some buses like HSIC would like to keep device in suspend state
after system resume.  The remote wakeup or interface activity
later will auto resume the device.  This will work only if the
device is auto suspended before system suspend.  If the device
runtime state had been active during system suspend and system
suspend routine put the device in suspend, it will not be resumed
during system resume.  When remote wakeup happen for this device,
the runtime resume will not bring the device to active as runtime
core think it is already active.

The HSIC bus ensure that device is auto suspended prior to system
suspend by holding a wakelock till the bus is suspended.  HSIC bus
is not handling the case where device is auto resumed immediately
after system suspend begins.  HSIC bus simply put the device into
suspend in system suspend routine.

This patch fixes above issue by returning an error code if the device
is not auto suspended during system suspend.  Also add a safe guard
check in HSIC system resume routine to skip device resume only if it
is auto suspended prior to system suspend.

CRs-Fixed: 422876
Change-Id: I888585ed872d808aa4dbca33b529fcc32994349b
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
This commit is contained in:
Pavankumar Kondeti 2012-11-09 10:54:00 +05:30 committed by Stephen Boyd
parent f01de74daf
commit d3bacb4de5
2 changed files with 10 additions and 3 deletions
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10
drivers/usb/core/driver.c
View File

@ -1411,8 +1411,14 @@ int usb_suspend(struct device *dev, pm_message_t msg)
{
struct usb_device *udev = to_usb_device(dev);
if (udev->bus->skip_resume && udev->state == USB_STATE_SUSPENDED)
return 0;
if (udev->bus->skip_resume) {
if (udev->state == USB_STATE_SUSPENDED) {
return 0;
} else {
dev_err(dev, "abort suspend\n");
return -EBUSY;
}
}
unbind_no_pm_drivers_interfaces(udev);

3
drivers/usb/host/ehci-msm-hsic.c
View File

@ -1859,7 +1859,8 @@ static int msm_hsic_pm_resume(struct device *dev)
* when remote wakeup is received or interface driver
* start I/O.
*/
if (!atomic_read(&mehci->pm_usage_cnt))
if (!atomic_read(&mehci->pm_usage_cnt) &&
pm_runtime_suspended(dev))
return 0;
ret = msm_hsic_resume(mehci);