[PATCH v2 1/2] USB: musb: fix session-bit runtime-PM quirk

* [PATCH v2 1/2] USB: musb: fix session-bit runtime-PM quirk
       [not found] <20170907133748.7400-1-johan@kernel.org>
@ 2017-09-07 13:37 ` Johan Hovold
  2017-09-07 13:37 ` [PATCH v2 2/2] USB: musb: fix late external abort on suspend Johan Hovold
       [not found] ` <20171005091436.GA2618@localhost>
  2 siblings, 0 replies; 6+ messages in thread
From: Johan Hovold @ 2017-09-07 13:37 UTC (permalink / raw)
  To: Bin Liu
  Cc: Tony Lindgren, Greg Kroah-Hartman, linux-usb,
	Sebastian Andrzej Siewior, Felipe Balbi, Johan Hovold, stable

The current session-bit quirk implementation does not prevent the retry
counter from underflowing, something which could break runtime PM and
keep the device active for a very long time (about 2^32 seconds) after a
disconnect.

This notably breaks the B-device timeout case, but could potentially
cause problems also when the controller is operating as an A-device.

Fixes: 2bff3916fda9 ("usb: musb: Fix PM for hub disconnect")
Cc: stable <stable@vger.kernel.org>     # 4.9
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/musb/musb_core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index b67692857daf..38fa3603554f 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1861,22 +1861,22 @@ static void musb_pm_runtime_check_session(struct musb *musb)
 		MUSB_DEVCTL_HR;
 	switch (devctl & ~s) {
 	case MUSB_QUIRK_B_INVALID_VBUS_91:
-		if (musb->quirk_retries--) {
+		if (musb->quirk_retries) {
 			musb_dbg(musb,
 				 "Poll devctl on invalid vbus, assume no session");
 			schedule_delayed_work(&musb->irq_work,
 					      msecs_to_jiffies(1000));
-
+			musb->quirk_retries--;
 			return;
 		}
 		/* fall through */
 	case MUSB_QUIRK_A_DISCONNECT_19:
-		if (musb->quirk_retries--) {
+		if (musb->quirk_retries) {
 			musb_dbg(musb,
 				 "Poll devctl on possible host mode disconnect");
 			schedule_delayed_work(&musb->irq_work,
 					      msecs_to_jiffies(1000));
-
+			musb->quirk_retries--;
 			return;
 		}
 		if (!musb->session)
-- 
2.14.1

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