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carl9170: fix usb pm suspend->resume woes

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This patch revamps some common code-paths which are
shared between (re-)initialization and suspend/resume
subroutines. It also adds some helpful comments
about quirks and associated difficulties.

It's quite big, but it should fix #25382:
<https://bugzilla.kernel.org/show_bug.cgi?id=25382>

And hopefully the code is robust enough to deal with
all possible suspend/resume scenarios without requiring
the user to do any sort of manual and possibly
dangerous work.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Christian Lamparter 2010-12-26 18:22:29 +01:00 committed by John W. Linville
parent 3b386510f4
commit 97e2c40269
1 changed files with 37 additions and 16 deletions
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53
drivers/net/wireless/ath/carl9170/usb.c
View file

@ -834,7 +834,7 @@ static int carl9170_usb_load_firmware(struct ar9170 *ar)
if (err)
goto err_out;
/* firmware restarts cmd counter */
/* now, start the command response counter */
ar->cmd_seq = -1;
return 0;
@ -851,7 +851,12 @@ int carl9170_usb_restart(struct ar9170 *ar)
if (ar->intf->condition != USB_INTERFACE_BOUND)
return 0;
/* Disable command response sequence counter. */
/*
* Disable the command response sequence counter check.
* We already know that the device/firmware is in a bad state.
* So, no extra points are awarded to anyone who reminds the
* driver about that.
*/
ar->cmd_seq = -2;
err = carl9170_reboot(ar);
@ -903,6 +908,15 @@ static int carl9170_usb_init_device(struct ar9170 *ar)
{
int err;
/*
* The carl9170 firmware let's the driver know when it's
* ready for action. But we have to be prepared to gracefully
* handle all spurious [flushed] messages after each (re-)boot.
* Thus the command response counter remains disabled until it
* can be safely synchronized.
*/
ar->cmd_seq = -2;
err = carl9170_usb_send_rx_irq_urb(ar);
if (err)
goto err_out;
@ -911,14 +925,21 @@ static int carl9170_usb_init_device(struct ar9170 *ar)
if (err)
goto err_unrx;
err = carl9170_usb_open(ar);
if (err)
goto err_unrx;
mutex_lock(&ar->mutex);
err = carl9170_usb_load_firmware(ar);
mutex_unlock(&ar->mutex);
if (err)
goto err_unrx;
goto err_stop;
return 0;
err_stop:
carl9170_usb_stop(ar);
err_unrx:
carl9170_usb_cancel_urbs(ar);
@ -964,10 +985,6 @@ static void carl9170_usb_firmware_finish(struct ar9170 *ar)
if (err)
goto err_freefw;
err = carl9170_usb_open(ar);
if (err)
goto err_unrx;
err = carl9170_register(ar);
carl9170_usb_stop(ar);
@ -1043,7 +1060,6 @@ static int carl9170_usb_probe(struct usb_interface *intf,
atomic_set(&ar->rx_work_urbs, 0);
atomic_set(&ar->rx_anch_urbs, 0);
atomic_set(&ar->rx_pool_urbs, 0);
ar->cmd_seq = -2;
usb_get_dev(ar->udev);
@ -1090,10 +1106,6 @@ static int carl9170_usb_suspend(struct usb_interface *intf,
carl9170_usb_cancel_urbs(ar);
/*
* firmware automatically reboots for usb suspend.
*/
return 0;
}
@ -1106,15 +1118,23 @@ static int carl9170_usb_resume(struct usb_interface *intf)
return -ENODEV;
usb_unpoison_anchored_urbs(&ar->rx_anch);
carl9170_set_state(ar, CARL9170_STOPPED);
/*
* The USB documentation demands that [for suspend] all traffic
* to and from the device has to stop. This would be fine, but
* there's a catch: the device[usb phy] does not come back.
*
* Upon resume the firmware will "kill" itself and the
* boot-code sorts out the magic voodoo.
* Not very nice, but there's not much what could go wrong.
*/
msleep(1100);
err = carl9170_usb_init_device(ar);
if (err)
goto err_unrx;
err = carl9170_usb_open(ar);
if (err)
goto err_unrx;
return 0;
err_unrx:
@ -1133,6 +1153,7 @@ static struct usb_driver carl9170_driver = {
#ifdef CONFIG_PM
.suspend = carl9170_usb_suspend,
.resume = carl9170_usb_resume,
.reset_resume = carl9170_usb_resume,
#endif /* CONFIG_PM */
};