On 3/16/2015 2:50 AM, Yunzhi Li wrote: > Hi >> When the HCD is disconnected, the DMA transfers still in-flight were cleaned-up >> but the count of available DMA channels (e.g. available_host_channels) was not >> reset. >> The pool of DMA channels can be depleted when doing unclean >> disconnection of USB peripherals, and reaches the point where no >> transfer was possible until the next reboot/reload of the driver. >> >> Tested by putting a programmable USB mux on the port and randomly >> plugging/unpluging a USB HUB with USB mass-storage key, USB-audio and >> USB-ethernet dongle connected to its downstream ports, and also doing the >> disconnection early while the devices are still enumerating to get more URBs >> in-flight. >> After the patch, the devices are still enumerating after thousands of cycles, >> while the port was totally dead before. >> >> Signed-off-by: Vincent Palatin <vpalatin@xxxxxxxxxxxx> >> --- >> I'm re-sending it, it seems the previous email did not show up. >> >> drivers/usb/dwc2/hcd.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c >> index c78c874..559b55e 100644 >> --- a/drivers/usb/dwc2/hcd.c >> +++ b/drivers/usb/dwc2/hcd.c >> @@ -257,6 +257,14 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg) >> */ >> channel->qh = NULL; >> } >> + /* All channels have been freed, mark them available */ >> + if (hsotg->core_params->uframe_sched > 0) { >> + hsotg->available_host_channels = >> + hsotg->core_params->host_channels; >> + } else { >> + hsotg->non_periodic_channels = 0; >> + hsotg->periodic_channels = 0; >> + } >> } >> >> /** > > I have reviewed this patch. Obviously,it makes sense. > > Reviewed-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx> Acked-by: John Youn <johnyoun@xxxxxxxxxxxx> -- 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