[PATCH] musb_host: fix lockup on rxcsr_h_error

[PATCH] musb_host: fix lockup on rxcsr_h_error

[Max Uvarov]

Fix soft lockup when resetting remote device attached
to usb host. Configuration:
pppd -> musb hub -> usb-serial -> gms modem
When gsm modem resets, musb rolls in incoming rx interrupts
which does not give any time to other application as result
it totally lock ups. Solution is to keep original logic for RXCSR_H_ERROR
and merge RXCSR_DATAERROR and RXCSR_H_ERROR branches to call same code
for setting rx stall with MUSB_RXCSR_H_WZC_BITS.

Signed-off-by: Max Uvarov <muvarov@gmail.com>
---
 drivers/usb/musb/musb_host.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index c3d5fc9..f82d0ae 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1592,14 +1592,13 @@ void musb_host_rx(struct musb *musb, u8 epnum)
 
 		/* stall; record URB status */
 		status = -EPIPE;
+	} else if (rx_csr & MUSB_RXCSR_DATAERROR ||
+		   rx_csr & MUSB_RXCSR_H_ERROR) {
 
-	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
-		dev_dbg(musb->controller, "end %d RX proto error\n", epnum);
-
-		status = -EPROTO;
-		musb_writeb(epio, MUSB_RXINTERVAL, 0);
-
-	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
+		if (rx_csr & MUSB_RXCSR_H_ERROR) {
+			status = -EPROTO;
+			musb_writeb(epio, MUSB_RXINTERVAL, 0);
+		}
 
 		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
 			dev_dbg(musb->controller, "RX end %d NAK timeout\n", epnum);
-- 
1.9.1

Re: [PATCH] musb_host: fix lockup on rxcsr_h_error

[Sergei Shtylyov]

Hello.

On 4/26/2016 9:45 AM, Max Uvarov wrote:

> Fix soft lockup when resetting remote device attached
> to usb host. Configuration:
> pppd -> musb hub -> usb-serial -> gms modem
> When gsm modem resets, musb rolls in incoming rx interrupts
> which does not give any time to other application as result
> it totally lock ups. Solution is to keep original logic for RXCSR_H_ERROR
> and merge RXCSR_DATAERROR and RXCSR_H_ERROR branches to call same code
> for setting rx stall with MUSB_RXCSR_H_WZC_BITS.
>
> Signed-off-by: Max Uvarov <muvarov@gmail.com>
> ---
>  drivers/usb/musb/musb_host.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
> index c3d5fc9..f82d0ae 100644
> --- a/drivers/usb/musb/musb_host.c
> +++ b/drivers/usb/musb/musb_host.c
> @@ -1592,14 +1592,13 @@ void musb_host_rx(struct musb *musb, u8 epnum)
>
>  		/* stall; record URB status */
>  		status = -EPIPE;
> +	} else if (rx_csr & MUSB_RXCSR_DATAERROR ||
> +		   rx_csr & MUSB_RXCSR_H_ERROR) {

	} else if (rx_csr & (MUSB_RXCSR_DATAERROR | MUSB_RXCSR_H_ERROR)) {

[...]

MBR, Sergei