From: Ming Lei <tom.leiming@xxxxxxxxx> This patch fixes the problem reported by Sergei: >how come? we need to send ZLP before giving back the request. >Well, look at the code ionce again. We need to send ZLP *after* >request->actual == request->length, but as the check is inserted >after the ZLP send, ZLP *may* be sent once the first DMA completes, >not the last. The patch also has been discussed on the link below: http://marc.info/?t=128454814900001&r=1&w=2 Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx> Reported-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxx> Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> Cc: Anand Gadiyar <gadiyar@xxxxxx> Cc: Mike Frysinger <vapier@xxxxxxxxxx> Signed-off-by: Felipe Balbi <balbi@xxxxxx> --- drivers/usb/musb/musb_gadget.c | 61 +++++++++++++++++++-------------------- 1 files changed, 30 insertions(+), 31 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index 18beb33..4b8bb5e 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -522,40 +522,39 @@ void musb_g_tx(struct musb *musb, u8 epnum) epnum, csr, musb_ep->dma->actual_len, request); } - if (is_dma || request->actual == request->length) { - /* - * First, maybe a terminating short packet. Some DMA - * engines might handle this by themselves. - */ - if ((request->zero && request->length - && request->length % musb_ep->packet_sz == 0) + /* + * First, maybe a terminating short packet. Some DMA + * engines might handle this by themselves. + */ + if ((request->zero && request->length + && (request->length % musb_ep->packet_sz == 0) + && (request->actual == request->length)) #ifdef CONFIG_USB_INVENTRA_DMA - || (is_dma && (!dma->desired_mode || - (request->actual & - (musb_ep->packet_sz - 1)))) + || (is_dma && (!dma->desired_mode || + (request->actual & + (musb_ep->packet_sz - 1)))) #endif - ) { - /* - * On DMA completion, FIFO may not be - * available yet... - */ - if (csr & MUSB_TXCSR_TXPKTRDY) - return; + ) { + /* + * On DMA completion, FIFO may not be + * available yet... + */ + if (csr & MUSB_TXCSR_TXPKTRDY) + return; - DBG(4, "sending zero pkt\n"); - musb_writew(epio, MUSB_TXCSR, MUSB_TXCSR_MODE - | MUSB_TXCSR_TXPKTRDY); - request->zero = 0; - } + DBG(4, "sending zero pkt\n"); + musb_writew(epio, MUSB_TXCSR, MUSB_TXCSR_MODE + | MUSB_TXCSR_TXPKTRDY); + request->zero = 0; + } - if (request->actual == request->length) { - musb_g_giveback(musb_ep, request, 0); - request = musb_ep->desc ? next_request(musb_ep) : NULL; - if (!request) { - DBG(4, "%s idle now\n", - musb_ep->end_point.name); - return; - } + if (request->actual == request->length) { + musb_g_giveback(musb_ep, request, 0); + request = musb_ep->desc ? next_request(musb_ep) : NULL; + if (!request) { + DBG(4, "%s idle now\n", + musb_ep->end_point.name); + return; } } -- 1.7.3.rc0.35.g8ac8c -- 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
