linux-kernel - Re: [PATCH] musb_host: fix lockup on rxcsr_h

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Message-ID: <0f5ea48a-fadd-1739-28d0-ef62d6abd65c@cogentembedded.com>
Date:	Tue, 26 Apr 2016 17:05:08 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Max Uvarov <muvarov@...il.com>, linux-kernel@...r.kernel.org
Cc:	linux-usb@...r.kernel.org, gregkh@...uxfoundation.org, balbi@...com
Subject: Re: [PATCH] musb_host: fix lockup on rxcsr_h_error

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@...il.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