From 7fd04a4fb26f351d01fa84485aa12204624be7fa Mon Sep 17 00:00:00 2001 From: Bin Liu Date: Mon, 24 Aug 2015 15:28:37 -0500 Subject: usb: musb: fix cppi channel teardown for isoch transfer commit b431ba8803666e56c1d178a421b3cbc36e8d3d33 upstream. After a few iterations of start/stop UVC camera streaming, the streaming stops. This patch adds 250us delay in the cppi channel abort path to let cppi drain properly. Using 50us delay seems to be too aggressive, some webcams are still broken. 250us is the original value used in TI 3.2 kernel. Signed-off-by: Bin Liu Signed-off-by: Felipe Balbi Cc: Oliver Neukum Signed-off-by: Jiri Slaby --- drivers/usb/musb/musb_cppi41.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c index 1c9c626248fd..2ed1695ff5ad 100644 --- a/drivers/usb/musb/musb_cppi41.c +++ b/drivers/usb/musb/musb_cppi41.c @@ -509,6 +509,9 @@ static int cppi41_dma_channel_abort(struct dma_channel *channel) } else { cppi41_set_autoreq_mode(cppi41_channel, EP_MODE_AUTOREQ_NONE); + /* delay to drain to cppi dma pipeline for isoch */ + udelay(250); + csr = musb_readw(epio, MUSB_RXCSR); csr &= ~(MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_DMAENAB); musb_writew(epio, MUSB_RXCSR, csr); -- cgit v1.2.3