From 111bbf69b6dde18e07c82803012bcd798f21de06 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 [ Upstream commit b431ba8803666e56c1d178a421b3cbc36e8d3d33 ] 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 Signed-off-by: Sasha Levin --- 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 6afbd0dedec6..8dfd86771fac 100644 --- a/drivers/usb/musb/musb_cppi41.c +++ b/drivers/usb/musb/musb_cppi41.c @@ -543,6 +543,9 @@ 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