I have USB card reader 6-in-1 based on Alcor Micro AU9360A22 chipset , and facing the same problem. Should I create a new bug report or use this one (since it is stil open)? $ lsusb Bus 003 Device 119: ID 058f:9360 Alcor Micro Corp. 8-in-1 Media Card Reader Ubuntu 14.04 Linux 3.13.0-43-generic #72-Ubuntu SMP Mon Dec 8 19:35:06 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux Problem: 1GB SD card works 4GB SD card does NOT work 32GB SD card does NOT work So simptomps are the same, when I inser the 4GB or 32GB cards, the card reader stops working. I have to re-plug the card reader to resolve the problem. Here are some messages from /var/log/syslog: (1) when I insert card reader into USB port Jan 3 17:45:02 yku-helix kernel: [59505.131128] usb 3-2.1: new full-speed USB device number 121 using xhci_hcd Jan 3 17:45:02 yku-helix kernel: [59505.152178] usb 3-2.1: New USB device found, idVendor=058f, idProduct=9360 Jan 3 17:45:02 yku-helix kernel: [59505.152189] usb 3-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Jan 3 17:45:02 yku-helix kernel: [59505.152194] usb 3-2.1: Product: Mass Storage Device Jan 3 17:45:02 yku-helix kernel: [59505.152199] usb 3-2.1: Manufacturer: Alcor Micro Jan 3 17:45:02 yku-helix kernel: [59505.152203] usb 3-2.1: SerialNumber: 9112181 Jan 3 17:45:02 yku-helix kernel: [59505.153136] usb-storage 3-2.1:1.0: USB Mass Storage device detected Jan 3 17:45:02 yku-helix kernel: [59505.153390] scsi16 : usb-storage 3-2.1:1.0 Jan 3 17:45:02 yku-helix mtp-probe: checking bus 3, device 121: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-2/3-2.1" Jan 3 17:45:02 yku-helix mtp-probe: bus: 3, device: 121 was not an MTP device Jan 3 17:45:03 yku-helix kernel: [59506.153255] scsi 16:0:0:0: Direct-Access Generic USB SD Reader 1.00 PQ: 0 ANSI: 0 Jan 3 17:45:03 yku-helix kernel: [59506.154293] scsi 16:0:0:1: Direct-Access Generic USB CF Reader 1.01 PQ: 0 ANSI: 0 Jan 3 17:45:03 yku-helix kernel: [59506.155255] scsi 16:0:0:2: Direct-Access Generic USB SM Reader 1.02 PQ: 0 ANSI: 0 Jan 3 17:45:03 yku-helix kernel: [59506.156219] scsi 16:0:0:3: Direct-Access Generic USB MS Reader 1.03 PQ: 0 ANSI: 0 Jan 3 17:45:03 yku-helix kernel: [59506.156746] sd 16:0:0:0: Attached scsi generic sg1 type 0 Jan 3 17:45:03 yku-helix kernel: [59506.157132] sd 16:0:0:1: Attached scsi generic sg2 type 0 Jan 3 17:45:03 yku-helix kernel: [59506.157473] sd 16:0:0:2: Attached scsi generic sg3 type 0 Jan 3 17:45:03 yku-helix kernel: [59506.157795] sd 16:0:0:3: Attached scsi generic sg4 type 0 Jan 3 17:45:04 yku-helix kernel: [59506.490191] sd 16:0:0:0: [sdb] Attached SCSI removable disk Jan 3 17:45:04 yku-helix kernel: [59506.493851] sd 16:0:0:1: [sdc] Attached SCSI removable disk Jan 3 17:45:04 yku-helix kernel: [59506.495283] sd 16:0:0:2: [sdd] Attached SCSI removable disk Jan 3 17:45:04 yku-helix kernel: [59506.496256] sd 16:0:0:3: [sde] Attached SCSI removable disk (2) when I insert 1GB SD card Jan 3 17:47:34 yku-helix kernel: [59656.710849] sd 16:0:0:0: [sdb] 1984000 512-byte logical blocks: (1.01 GB/968 MiB) Jan 3 17:47:34 yku-helix kernel: [59656.713034] sd 16:0:0:0: [sdb] No Caching mode page found Jan 3 17:47:34 yku-helix kernel: [59656.713037] sd 16:0:0:0: [sdb] Assuming drive cache: write through Jan 3 17:47:34 yku-helix kernel: [59656.717153] sd 16:0:0:0: [sdb] No Caching mode page found Jan 3 17:47:34 yku-helix kernel: [59656.717155] sd 16:0:0:0: [sdb] Assuming drive cache: write through Jan 3 17:47:34 yku-helix kernel: [59656.723027] sdb: sdb1 Jan 3 17:47:36 yku-helix kernel: [59658.740389] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: (null) Jan 3 17:47:36 yku-helix udisksd[2914]: Mounted /dev/sdb1 at /media/yku/529bb3e8-8836-4b34-b21b-39d16aade719 on behalf of uid 1000 (3) when I insert 4GB or 32GB SD card Note that when I insert the 4GB or 32GB cards I see the CPU spike in I/O Wait (for about 30 sec) from "System Load Indicator" and then the following error logs Jan 3 17:48:52 yku-helix kernel: [59734.998532] usb 3-2.1: reset full-speed USB device number 121 using xhci_hcd Jan 3 17:48:52 yku-helix kernel: [59735.016735] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e600 Jan 3 17:48:52 yku-helix kernel: [59735.016739] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e640 Jan 3 17:49:02 yku-helix kernel: [59745.097966] usb 3-2.1: reset full-speed USB device number 121 using xhci_hcd Jan 3 17:49:02 yku-helix kernel: [59745.116120] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e600 Jan 3 17:49:02 yku-helix kernel: [59745.116144] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e640 Jan 3 17:49:18 yku-helix kernel: [59761.204535] usb 3-2.1: reset full-speed USB device number 121 using xhci_hcd Jan 3 17:49:18 yku-helix kernel: [59761.222694] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e600 Jan 3 17:49:18 yku-helix kernel: [59761.222706] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e640 Jan 3 17:49:18 yku-helix kernel: [59761.292712] usb 3-2.1: reset full-speed USB device number 121 using xhci_hcd Jan 3 17:49:18 yku-helix kernel: [59761.310615] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e600 Jan 3 17:49:18 yku-helix kernel: [59761.310619] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e640 Jan 3 17:49:28 yku-helix kernel: [59771.392405] usb 3-2.1: reset full-speed USB device number 121 using xhci_hcd Jan 3 17:49:28 yku-helix kernel: [59771.410311] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e600 Jan 3 17:49:28 yku-helix kernel: [59771.410323] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88020d77e640 Jan 3 17:49:28 yku-helix kernel: [59771.410778] sd 16:0:0:0: Device offlined - not ready after error recovery Thank you. Yura.