From e75df37165c639b06213ec88b4763c3e50a7f079 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 16 Nov 2010 23:37:37 +0800 Subject: [PATCH] usb: musb: clear RXCSR_AUTOCLEAR before PIO read If RXCSR_AUTOCLEAR flag is not cleard before PIO reading, one packet may be recieved by musb fifo, but no chance to notify software, so cause packet loss, follows the detailed process: - PIO read one packet - musb fifo auto clear the MUSB_RXCSR_RXPKTRDY - musb continue to recieve the next packet, and MUSB_RXCSR_RXPKTRDY is set - software clear the MUSB_RXCSR_RXPKTRDY, so there is no chance for musb to notify software that the 2nd recieved packet. The patch does fix the g_ether issue below: - use fifo_mode 3 to enable double buffer - 'ping -s 1024 IP_OF_BEAGLE_XM' - one usb packet of 512 byte is lost, so ping failed, which can be observed by wireshark note: Beagle xm takes musb rtl1.8 and may fallback to pio mode for unaligned buffer. Signed-off-by: Ming Lei Signed-off-by: Felipe Balbi --- drivers/usb/musb/musb_gadget.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index 0169dcf3a6ff..363cfad003f8 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -765,10 +765,11 @@ static void rxstate(struct musb *musb, struct musb_request *req) if (is_dma_capable() && musb_ep->dma) { unmap_dma_buffer(req, musb); - /* Clear DMAENAB for the + /* + * Clear DMAENAB and AUTOCLEAR for the * PIO mode transfer */ - csr &= ~MUSB_RXCSR_DMAENAB; + csr &= ~(MUSB_RXCSR_DMAENAB | MUSB_RXCSR_AUTOCLEAR); musb_writew(epio, MUSB_RXCSR, csr); } -- 2.34.1