Messages in this thread | | | Subject | Re: [PATCH 2/2] usb: musb: Stop bulk endpoint while queue is rotated | From | Sergei Shtylyov <> | Date | Fri, 20 May 2016 20:14:09 +0300 |
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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@cambrionix.com> >>> Cc: stable@vger.kernel.org >>> --- >>> 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.
> Andrew
MBR, Sergei
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