Patch "usb: musb: Check for host-mode using is_host_active() on reset interrupt" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

usb: musb: Check for host-mode using is_host_active() on reset interrupt

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-musb-check-for-host-mode-using-is_host_active-on-reset-interrupt.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jonathan Liu <[email protected]>
Date: Mon, 9 Oct 2017 22:46:12 -0500
Subject: usb: musb: Check for host-mode using is_host_active() on reset interrupt

From: Jonathan Liu <[email protected]>

commit 445ef61543da3db5b699f87fb0aa4f227165f6ed upstream.

The sunxi musb has a bug where sometimes it will generate a babble error on device disconnect instead of a disconnect IRQ. When this happens the musb controller switches from host mode to device mode (it clears MUSB_DEVCTL_HM/MUSB_DEVCTL_SESSION and sets MUSB_DEVCTL_BDEVICE) and gets stuck in this state.

The babble error is misdetected as a bus reset because MUSB_DEVCTL_HM was cleared.

To fix this, use is_host_active() rather than (devctl & MUSB_DEVCTL_HM) to detect babble error so that sunxi musb babble recovery can handle it by restoring the mode. This information is provided by the driver logic and does not rely on register contents.

---
 drivers/usb/musb/musb_core.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

@@ -890,7 +890,7 @@ b_host:
 	 */
 	if (int_usb & MUSB_INTR_RESET) {
 		handled = IRQ_HANDLED;
-		if (devctl & MUSB_DEVCTL_HM) {
+		if (is_host_active(musb)) {
 			/*
 			 * When BABBLE happens what we can depends on which
 			 * platform MUSB is running, because some platforms

@@ -900,9 +900,7 @@ b_host:
 			 * drop the session.
 			 */
 			dev_err(musb->controller, "Babble\n");
-
-			if (is_host_active(musb))
-				musb_recover_from_babble(musb);
+			musb_recover_from_babble(musb);
 		} else {
 			musb_dbg(musb, "BUS RESET as %s",
 				usb_otg_state_string(musb->xceiv->otg->state));

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/usb-musb-check-for-host-mode-using-is_host_active-on-reset-interrupt.patch queue-4.9/usb-musb-sunxi-explicitly-release-usb-phy-on-exit.patch