Re: MUSB interrupt storm on device removal

[Bin Liu <b-liu@xxxxxx>]

On Tue, Jan 22, 2019 at 05:19:39PM +0000, Måns Rullgård wrote:
> Bin Liu <b-liu@xxxxxx> writes:
> 
> > On Mon, Jan 21, 2019 at 09:20:52PM +0000, Måns Rullgård wrote:
> >> Bin Liu <b-liu@xxxxxx> writes:
> >> 
> >> > On Fri, Jan 18, 2019 at 08:15:02PM +0000, Måns Rullgård wrote:
> >> >> Bin Liu <b-liu@xxxxxx> writes:
> >> >> 
> >> >> > On Mon, Dec 17, 2018 at 09:36:17PM +0000, Måns Rullgård wrote:
> >> >> >> Bin Liu <b-liu@xxxxxx> writes:
> >> >> >> 
> >> >> >> > On Mon, Dec 17, 2018 at 07:16:08PM +0000, Måns Rullgård wrote:
> >> >> >> >> Bin Liu <b-liu@xxxxxx> writes:
> >> >> >> >> 
> >> >> >> >> > Hi,
> >> >> >> >> >
> >> >> >> >> > On Mon, Dec 17, 2018 at 03:13:12PM +0000, Måns Rullgård wrote:
> >> >> >> >> >> I have a strange problem with the musb driver in host mode on AM3358
> >> >> >> >> >> (beaglebone) hardware.  If I connect a multi-port serial adapter and
> >> >
> >> > Is this on beaglebone or beagleboneblack?
> >> 
> >> We've seen it with Beaglebone Enhanced [1] and BeagleCore [2] based
> >> devices.  Both are based on the AM3358 and mostly compatible with the
> >> Beaglebone Black.
> >> 
> >> [1] https://elinux.org/SanCloud_BeagleBoneEnhanced
> >> [2] http://beaglecore.com/products/bcm1str.html
> >
> > Okay, now I see you have a hub on the board. I just reproduced the
> > console lockup after added a hub in my setup. I will find some time to
> > debug this.
> >
> > FYI, there was a similar issue in a few years ago, which was that the
> > hub routine never got called during the storm then the device disconnect
> > event never got populated from the hub driver. I am wondering if this is
> > the same issue pops up again...
> 
> Now that you mentioned the hub, I tried connecting the serial adapter to
> the OTG port (in host mode) on the Beaglebone Enhanced (it's not
> normally used in this product).  When connected directly, the disconnect
> indeed works properly.  With a hub in between, it breaks.

Please use the following hack as a workaround for now. I will think more
about it.

Regards,
-Bin.

--------8<----------
diff git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index b59ce9ad14ce..3719f6d9b26c 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1811,7 +1811,7 @@ void musb_host_rx(struct musb *musb, u8 epnum)
        } else if (rx_csr & MUSB_RXCSR_H_ERROR) {
                musb_dbg(musb, "end %d RX proto error", epnum);
 
-               status = -EPROTO;
+               status = -EPIPE;
                musb_writeb(epio, MUSB_RXINTERVAL, 0);
 
                rx_csr &= ~MUSB_RXCSR_H_ERROR;