I think this is my issue too. It affects me on Maverick 64 bit as well as Natty beta2 32bit LiveCD.
My steps: 1. boot up with Natty 32bit beta 2 LiveUSB 2. install nfs-common 3. mount an nfs store 4. did some suspend-resume testing 5. inserted a USB flash drive Error: Unable to mount CANON_DC A job is pending on /dev/sdg1 Apr 24 15:59:04 ubuntu kernel: [ 3852.153784] usb 10-4: new high speed USB device using xhci_hcd and address 22 Apr 24 15:59:04 ubuntu kernel: [ 3852.171606] xhci_hcd 0000:02:00.0: WARN: short transfer on control ep Apr 24 15:59:04 ubuntu kernel: [ 3852.172055] xhci_hcd 0000:02:00.0: WARN: short transfer on control ep Apr 24 15:59:04 ubuntu kernel: [ 3852.172443] xhci_hcd 0000:02:00.0: WARN: short transfer on control ep Apr 24 15:59:04 ubuntu kernel: [ 3852.172927] xhci_hcd 0000:02:00.0: WARN: short transfer on control ep Apr 24 15:59:04 ubuntu kernel: [ 3852.174111] scsi46 : usb-storage 10-4:1.0 Apr 24 15:59:05 ubuntu kernel: [ 3853.173751] scsi 46:0:0:0: Direct-Access Single Flash Reader 1.00 PQ: 0 ANSI: 0 Apr 24 15:59:05 ubuntu kernel: [ 3853.175151] sd 46:0:0:0: Attached scsi generic sg7 type 0 Apr 24 15:59:05 ubuntu kernel: [ 3853.597743] sd 46:0:0:0: [sdg] 62720 512-byte logical blocks: (32.1 MB/30.6 MiB) Apr 24 15:59:05 ubuntu kernel: [ 3853.597954] xhci_hcd 0000:02:00.0: WARN: Stalled endpoint Apr 24 15:59:05 ubuntu kernel: [ 3853.598479] sd 46:0:0:0: [sdg] Write Protect is off Apr 24 15:59:05 ubuntu kernel: [ 3853.598485] sd 46:0:0:0: [sdg] Mode Sense: 03 00 00 00 Apr 24 15:59:05 ubuntu kernel: [ 3853.599028] sd 46:0:0:0: [sdg] No Caching mode page present Apr 24 15:59:05 ubuntu kernel: [ 3853.599034] sd 46:0:0:0: [sdg] Assuming drive cache: write through Apr 24 15:59:05 ubuntu kernel: [ 3853.600561] xhci_hcd 0000:02:00.0: WARN: Stalled endpoint Apr 24 15:59:05 ubuntu kernel: [ 3853.601439] sd 46:0:0:0: [sdg] No Caching mode page present Apr 24 15:59:05 ubuntu kernel: [ 3853.601444] sd 46:0:0:0: [sdg] Assuming drive cache: write through Apr 24 15:59:05 ubuntu kernel: [ 3853.604333] sdg: sdg1 Apr 24 15:59:05 ubuntu kernel: [ 3853.606715] xhci_hcd 0000:02:00.0: WARN: Stalled endpoint Apr 24 15:59:05 ubuntu kernel: [ 3853.607607] sd 46:0:0:0: [sdg] No Caching mode page present Apr 24 15:59:05 ubuntu kernel: [ 3853.607613] sd 46:0:0:0: [sdg] Assuming drive cache: write through Apr 24 15:59:05 ubuntu kernel: [ 3853.607617] sd 46:0:0:0: [sdg] Attached SCSI removable disk Apr 24 16:00:29 ubuntu kernel: [ 3937.126803] CE: hpet5 increased min_delta_ns to 7500 nsec Apr 24 16:00:29 ubuntu kernel: [ 3937.126812] CE: hpet5 increased min_delta_ns to 11250 nsec -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/647973 Title: USB 3.0 on 10.10 x86_64 : xhci_hcd WARN: Stalled endpoint -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs