On Fri, 2 Dec 2011, Sarah Sharp wrote: > When a USB device is disconnected (or a driver is unbound from a > device), the USB core will automatically cancel any URBs, and possibly > clean up any host controller state associated with the device. This may > include setting the alternate interface setting back to alt setting 0. > > Unfortunately, the xHCI needs any bulk stream rings to be freed before > the next alt setting is installed, and the USB core has no idea which > endpoints has stream rings allocated. Instead, the UAS driver needs to > set the soft_unbind flag, which tells the USB core that it will cancel > any pending URBs and clean up any extra state (including the stream > rings). That's right. > Make the UAS disconnect method go through the same process as the > pre_reset method to quiesce all command submission, wait for all URBs to > be killed, and free the stream rings. Not the same method at all. You have to call scsi_remove_host() first, so that the SCSI layer can clean up after itself. Once that's done, it's okay to go through the pre_reset procedue. (If the SCSI layer behaves properly, it shouldn't have any active commands after scsi_remove_host() returns, anyway, so pre_reset won't have anything to do.) Alan Stern -- 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
