Am Dienstag, 31. Januar 2012, 14:58:07 schrieb Bjørn Mork: > We need to ensure that no URBs are submitted during reset. Taking any of > the mutexes can deadlock against either wdm_read or wdm_write. Use the > WDM_SUSPENDING flag instead to indicate that no IO is possible, as the > requirements for suspend and reset are similar No, the requirements are not similar. wdm_write() can resume a device. During a reset you must wait (or -EAGAIN in the non-blocking case). The device has been reset or is being reset. This means that previous settings may have been erased. So we must a) return an error for read and write b) accept no new write until the reset is finished (wait or -EAGAIN) The mutex allowed this, but we a problem you have noted. But you cannot use WDM_SUSPENDING for this because it is not tested when it would need to be tested. And we need to wait in the write() code path. Regards Oliver -- 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
