Final detail: The fellow experiencing the identical problem with both Gentoo and mainline 3.1.1 reports that his failing USB3 enclosure reports itself as a JMicron USB3-to-SATA bridge: $ lsusb -v Bus 001 Device 009: ID 152d:0539 JMicron Technology Corp. / JMicron USA Technology Corp. Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.10 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x152d JMicron Technology Corp. / JMicron USA Technology Corp. idProduct 0x0539 bcdDevice 1.00 iManufacturer 10 JMicron iProduct 11 USB3.0 to SATA Bridge The failure behavior is a perfect match to the WDC MyBook device here, which strongly suggests that WD is using this controller but as taken the extra effort to replace the device strings. If anyone else has a USB3 drive enclosure with this controller or a MyBook, it would be interesting to see if they can reproduce this issue. Be sure that 4K sectors are aligned for the test. Default partitions created with 'fdisk' are off by one sector and will slow it down, possibly enough to hide the bug. -- 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
