carl9170: fix usb pm suspend->resume woes
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>
diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
index 2d947a3..537732e 100644
--- a/drivers/net/wireless/ath/carl9170/usb.c
+++ b/drivers/net/wireless/ath/carl9170/usb.c
@@ -834,7 +834,7 @@
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 @@
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 @@
{
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 @@
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 @@
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 @@
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 @@
carl9170_usb_cancel_urbs(ar);
- /*
- * firmware automatically reboots for usb suspend.
- */
-
return 0;
}
@@ -1106,15 +1118,23 @@
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 @@
#ifdef CONFIG_PM
.suspend = carl9170_usb_suspend,
.resume = carl9170_usb_resume,
+ .reset_resume = carl9170_usb_resume,
#endif /* CONFIG_PM */
};