> From: Sergei Shtylyov [mailto:sergei.shtylyov@xxxxxxxxxxxxxxxxxx] > > Hello. > > On 5/23/2016 3:00 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 > > --- > > V2 added comment about clearing REQPKT before DATAERR_NAKTIMEOUT > > > > drivers/usb/musb/musb_host.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/usb/musb/musb_host.c > > b/drivers/usb/musb/musb_host.c index 2966596..676cb98 100644 > > --- a/drivers/usb/musb/musb_host.c > > +++ b/drivers/usb/musb/musb_host.c > > @@ -997,6 +997,12 @@ 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; > > + /* > > + * Need to stop the transaction by clearing REQPKT before > > Transcation? Maybe transfer? The quote from the TRM is "If the DATAERR_NAKTIMEOUT bit is set, the controller can be directed either to continue trying this transaction (until it times out again) by clearing the DATAERR_NAKTIMEOUT bit or to abort the transaction by clearing REQPKT bit before clearing the DATAERR_NAKTIMEOUT bit." So 'transaction' is correct. > > + * DATAERR_NAKTIMEOUT ref TRM section 16.3.8.2.2.1.2 > > Which TRM? Do you understand that the MUSB core is used by multiple > SoCs? > I'd recommend referring just to the "abstract" manual or the MUSB > programmer's guide (section 9.2.2 if you want an exact ref.). That would be the AM335x Sitara Processors TRM. I don't have the MUSB programmer's guide, is it available online somewhere? I do not understand what you mean by the "abstract" manual. Would you be OK with "ref MUSB Programmer's Guide section 9.2.2" 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
