The "no-resource" error occurs when the driver issues DEPSTRTXFER command to start data transfer on specific endpoint, and dwc3 core throws error "no resource" available to process the request. This condition is occurs in composite gadget scenario where there are multiple interfaces selected by host and during simulateneous data traffic on multiple endpoints on these interfaces, the issue occur when software/driver issues DEPSTRTXFER command to specific endpoint in same direction (in/out) and other endpoint in the same direction (in/out) is busy or executed by dwc3 controller. example: if dwc3 core is busy in transferring the request on ep1-in during this scenario, if software/driver queues another request on ep2-in and issue start transfer (DEPSTRTXFER command), then dwc3 throws error "no-resource". The same applicable to OUT transfer. The issue is root caused that software issue DEPSTARTCFG "START NEW CONFIGURATION" command twice during the SET_INTERFACE request received from host while selecting multiple interface. In single configuration with two parallel interfaces, say the interface-1 has two endpoints, ep1-in & ep1-out, and interface-2 has two endpoints ep2-in and ep2-out. The additional DEPSTARTCFG will make the core too allocate the same resource, say for ep2-in and ep2-out which were previously assigned to ep1-in and ep1-out. Therefore during the simulataneous traffic on endpoints on same direction leads to resource conflict and dwc3 core throws the "no-resource" error when DEPSTARTCFG command while issuing the start transfer request. Hence the DEPSTARTCFG must be issued only once after reset and during SET_CONFIG request from host to allocate the transfer resource properly for all endpoints on multiple interfaces in composite gadget scenario. The issue is reproducible in composite gadget (ACM + NCM) enabled through CONFIGFS. Signed-off-by: Ravi Babu <ravibabu@xxxxxx> --- drivers/usb/dwc3/ep0.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 3a9354a..97499a2 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -739,7 +739,6 @@ static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl) break; case USB_REQ_SET_INTERFACE: dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_INTERFACE"); - dwc->start_config_issued = false; /* Fall through */ default: dwc3_trace(trace_dwc3_ep0, "Forwarding to gadget driver"); -- 1.7.9.5 -- 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
