On Fri, Apr 04, 2014 at 11:01:06AM +0200, Jakub Kiciński wrote: > On Fri, 4 Apr 2014 10:19:09 +0200, Stanislaw Gruszka wrote: > > On Thu, Apr 03, 2014 at 05:37:01PM +0200, Jakub Kiciński wrote: > > > On Thu, 3 Apr 2014 16:12:07 +0200, Richard Genoud wrote: > > > > rt2x00usb_register_read_lock() calls rt2x00usb_vendor_req_buff_lock() > > > > that calls rt2x00usb_vendor_request() which is already looping up to > > > > REGISTER_BUSY_COUNT times. > > > > > > > > So this loop is not needed. > > > > > > Not true. rt2x00usb_vendor_request() busy-waits for usb_control_msg() > > > to succeed, rt2x00usb_register_read_lock() busy-waits for the register > > > field itself to become 0. > > > > Yeah, but still we are looping REGISTER_BUSY_COUNT*REGISTER_BUSY_COUNT > > what seems to be far too long. > > Yes, the busy waiting itself takes roughly 1s (100*100*100us) and then > there are transfer times, so it might be too long indeed. Vendor driver > waits only 10 * 5ms in RTUSB_VendorRequest() so We use "timeout" argument which is set to 500ms , so perhaps that could be the reason why Richard sees "infinite" loop i.e. 100*100*(500ms + 100us) > rt2x00usb_vendor_request() seems like a better place to cut down the > number of loops. > > Alternatively we could make rt2x00usb_regbusy_read() check the retval > from rt2x00usb_vendor_request() and exit early? Make sense, but I think we should review the area and make some more changes to fine tune the timeout of USB reg reading functions. Stanislaw -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
