From 1b967691ecdcf512bc33c0783158f760e5c1a9cf Mon Sep 17 00:00:00 2001 From: Bin Liu Date: Sun, 24 May 2020 21:50:44 -0500 Subject: [PATCH] usb: musb: return -ESHUTDOWN in urb when three-strikes error happened When a USB device attached to a hub got disconnected, MUSB controller generates RXCSR_RX_ERROR interrupt for the 3-strikes-out error. Currently the MUSB host driver returns -EPROTO in current URB, then the USB device driver could immediately resubmit the URB which causes MUSB generate RXCSR_RX_ERROR interrupt again. This circle causes interrupt storm then the hub never got a chance to report the USB device detach. To fix the interrupt storm, change the URB return code to -ESHUTDOWN for MUSB_RXCSR_H_ERROR interrupt, so that the USB device driver will not immediately resubmit the URB. Signed-off-by: Bin Liu Link: https://lore.kernel.org/r/20200525025049.3400-2-b-liu@ti.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/musb_host.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 8736f4251a22..8b7d22a0c0fb 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -1774,9 +1774,15 @@ void musb_host_rx(struct musb *musb, u8 epnum) status = -EPIPE; } else if (rx_csr & MUSB_RXCSR_H_ERROR) { - musb_dbg(musb, "end %d RX proto error", epnum); + dev_err(musb->controller, "ep%d RX three-strikes error", epnum); - status = -EPROTO; + /* + * The three-strikes error could only happen when the USB + * device is not accessible, for example detached or powered + * off. So return the fatal error -ESHUTDOWN so hopefully the + * USB device drivers won't immediately resubmit the same URB. + */ + status = -ESHUTDOWN; musb_writeb(epio, MUSB_RXINTERVAL, 0); rx_csr &= ~MUSB_RXCSR_H_ERROR; -- 2.11.0