From dbac5d07d13e330e6706813c9fde477140fb5d80 Mon Sep 17 00:00:00 2001 From: Bin Liu Date: Tue, 31 May 2016 10:05:04 -0500 Subject: usb: musb: host: don't start next rx urb if current one failed urb->status is set when endpoint csr RXSTALL, H_ERROR, DATAERROR or INCOMPRX bit is set. Those bits mean a broken pipe, so don't start next urb when any of these bits is set by checking urb->status. To minimize the risk of regression, only do so for RX, until we have a test case to understand the behavior of TX. The patch fixes system freeze issue caused by repeatedly invoking RX ISR while removing a usb uart device connected to a hub, in which case the hub has no chance to report the disconnect event due to the kernel is busy in processing the RX interrupt flooding. Fix checkpatch complaint (qh != NULL) as while. Reported-by: Max Uvarov Tested-by: Yegor Yefremov Signed-off-by: Bin Liu Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/musb_host.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/usb') diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 931381c51ad7..dd1ebde02786 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -434,7 +434,13 @@ static void musb_advance_schedule(struct musb *musb, struct urb *urb, } } - if (qh != NULL && qh->is_ready) { + /* + * The pipe must be broken if current urb->status is set, so don't + * start next urb. + * TODO: to minimize the risk of regression, only check urb->status + * for RX, until we have a test case to understand the behavior of TX. + */ + if ((!status || !is_in) && qh && qh->is_ready) { dev_dbg(musb->controller, "... next ep%d %cX urb %p\n", hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh)); musb_start_urb(musb, is_in, qh); -- cgit v1.2.3-59-g8ed1b