> From: Sergei Shtylyov [mailto:sergei.shtylyov@xxxxxxxxxxxxxxxxxx] > On 05/20/2016 08:06 PM, Andrew Goodbody wrote: > > >>> Ensure that the endpoint is stopped by clearing REQPKT before > >>> clearing DATAERR_NAKTIMEOUT before rotating the queue on the > >>> dedicated bulk endpoint. > >>> This addresses an issue where a race could result in the endpoint > >>> receiving data before it was reprogrammed resulting in a warning > >>> about such data from musb_rx_reinit before it was thrown away. > >>> The data thrown away was a valid packet that had been correctly > >>> ACKed which meant the host and device got out of sync. > >>> > >>> Signed-off-by: Andrew Goodbody > <andrew.goodbody@xxxxxxxxxxxxxx> > >>> Cc: stable@xxxxxxxxxxxxxxx > >>> --- > >>> drivers/usb/musb/musb_host.c | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>> diff --git a/drivers/usb/musb/musb_host.c > >>> b/drivers/usb/musb/musb_host.c index 30e0d65..777ff30 100644 > >>> --- a/drivers/usb/musb/musb_host.c > >>> +++ b/drivers/usb/musb/musb_host.c > >>> @@ -999,6 +999,8 @@ static void musb_bulk_nak_timeout(struct musb > >> *musb, struct musb_hw_ep *ep, > >>> /* clear nak timeout bit */ > >>> rx_csr = musb_readw(epio, MUSB_RXCSR); > >>> rx_csr |= MUSB_RXCSR_H_WZC_BITS; > >>> + rx_csr &= ~MUSB_RXCSR_H_REQPKT; > >>> + musb_writew(epio, MUSB_RXCSR, rx_csr); > >>> rx_csr &= ~MUSB_RXCSR_DATAERROR; > >>> musb_writew(epio, MUSB_RXCSR, rx_csr); > >> > >> Can we not clear both in one write? > > > > Section 16.3.8.2.2.1.2 of the TRM says to clear REQPKT before > DATAERR_NAKTIMEOUT. > > Right, the MUSB programmer's guide also says that. Then a comment > wouldn't hurt here. I'll add that for v2, thanks. Andrew > > Andrew > > MBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
