通过 USB 连接将数据传输到我的 MP3 播放器的速度非常慢。
我有一个来自 Samsung 的 mp3 播放器 (YP-M1JCB/EDC)，我已将其连接到我的 Fedora linux（电脑连接在mp3播放器中设置为MSC，即大容量存储设备类）。
当我使用 USB 电缆将 mp3 播放器连接到计算机时，dmesg我看到以下内容：
[1351555.669080] usb 2-2: new high-speed USB device number 17 using ehci-pci
[1351555.812993] usb 2-2: New USB device found, idVendor=04e8, idProduct=5123
[1351555.813047] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[1351555.813059] usb 2-2: Product: YP-M1
[1351555.813065] usb 2-2: Manufacturer: Samsung Electronics
[1351555.813071] usb 2-2: SerialNumber: b37c03ac0f1647c2a9720aae4e913080
[1351555.896394] scsi47 : usb-storage 2-2:1.0
[1351556.899771] scsi 47:0:0:0: Direct-Access Samsung YP-M1 1.0 PQ: 0 ANSI: 0
[1351556.900481] scsi 47:0:0:1: Direct-Access Samsung microSD 1.0 PQ: 0 ANSI: 0
[1351556.902422] sd 47:0:0:0: Attached scsi generic sg3 type 0
[1351556.904403] sd 47:0:0:0: [sdc] 1896703 4096-byte logical blocks: (7.76 GB/7.23 GiB)
[1351556.904617] sd 47:0:0:1: Attached scsi generic sg4 type 0
[1351556.904922] sd 47:0:0:0: [sdc] Write Protect is off
[1351556.904930] sd 47:0:0:0: [sdc] Mode Sense: 00 06 00 00
[1351556.907342] sd 47:0:0:0: [sdc] Asking for cache data failed
[1351556.907361] sd 47:0:0:0: [sdc] Assuming drive cache: write through
[1351556.910613] sd 47:0:0:1: [sdd] Attached SCSI removable disk
[1351556.911467] sd 47:0:0:0: [sdc] 1896703 4096-byte logical blocks: (7.76 GB/7.23 GiB)
[1351556.912448] sd 47:0:0:0: [sdc] Asking for cache data failed
[1351556.912457] sd 47:0:0:0: [sdc] Assuming drive cache: write through
[1351556.913372] sdc: sdc1
[1351556.916978] sd 47:0:0:0: [sdc] 1896703 4096-byte logical blocks: (7.76 GB/7.23 GiB)
[1351556.919093] sd 47:0:0:0: [sdc] Asking for cache data failed
[1351556.919111] sd 47:0:0:0: [sdc] Assuming drive cache: write through
[1351556.919120] sd 47:0:0:0: [sdc] Attached SCSI removable disk
对我来说似乎没问题。
然后我安装设备/dev/sdc1：
sudo mount -o uid=erik /dev/sdc1 /mnt/usb-stick/
当我在设备上创建一个小文本文件，然后卸载它时，似乎没有问题。我可以读取设备上的文本文件（它有一个文本阅读应用程序）。
但是，当我将一些较大的文件（mp3 文件）复制到设备时，需要很长时间。嗯，命令行
cp supermusic.mp3 /mnt/usb-stick/Music/
几秒钟后完成。但是当我尝试卸载设备时，它永远不会完成。dmesg显示：
[1352056.822086] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352087.878103] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352118.854062] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352149.830105] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352180.870081] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352211.846060] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352211.969584] sd 48:0:0:0: [sdc] Unhandled error code
[1352211.969601] sd 48:0:0:0: [sdc]
[1352211.969607] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK
[1352211.969612] sd 48:0:0:0: [sdc] CDB:
[1352211.969617] Write(10): 2a 00 00 1b 51 02 00 00 1e 00
[1352211.969634] end_request: I/O error, dev sdc, sector 14321680
[1352242.822056] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352273.862064] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352304.838066] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352335.814100] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352366.854074] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352397.830096] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352397.954124] sd 48:0:0:0: [sdc] Unhandled error code
[1352397.954141] sd 48:0:0:0: [sdc]
[1352397.954147] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK
[1352397.954153] sd 48:0:0:0: [sdc] CDB:
[1352397.954157] Write(10): 2a 00 00 1b 51 20 00 00 1e 00
[1352397.954174] end_request: I/O error, dev sdc, sector 14321920
[1352428.870469] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352459.846068] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352490.822088] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352521.862078] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352552.838052] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352583.878077] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352584.005386] sd 48:0:0:0: [sdc] Unhandled error code
[1352584.005401] sd 48:0:0:0: [sdc]
[1352584.005407] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK
[1352584.005413] sd 48:0:0:0: [sdc] CDB:
[1352584.005417] Write(10): 2a 00 00 1b 51 3e 00 00 1e 00
[1352584.005434] end_request: I/O error, dev sdc, sector 14322160
[1352614.854055] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352628.359667] usb 1-2: USB disconnect, device number 46
[1352645.830068] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352676.870073] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352707.846090] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352738.822066] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352769.862077] usb 2-2: reset high-speed USB device number 18 using ehci-pci
[1352769.985579] sd 48:0:0:0: [sdc] Unhandled error code
[1352769.985596] sd 48:0:0:0: [sdc]
[1352769.985601] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK
[1352769.985608] sd 48:0:0:0: [sdc] CDB:
[1352769.985611] Write(10): 2a 00 00 1b 51 5c 00 00 1e 00
[1352769.985630] end_request: I/O error, dev sdc, sector 14322400
似乎有些问题，但是为什么呢？我已经连接了许多其他大容量存储设备，但从未遇到过问题。
如何查看数据是否仍在传输？有多快？如果我转到 /mnt/usb-stick/Music 该文件似乎已经在那里（完整大小）。
PS：当我等待很长时间后拔掉 USB 电缆时，当我重新连接它并在分区上启动 fsck.vfat 时，它发现了大量带有中文字形的错误，需要很长时间才能修复。
答案1
USB 连接重置表明您的 USB 设备（或者可能是电气连接）存在物理问题。其他驱动器没有出现该问题的事实支持了这一理论。
日志证实了这一点。 （“end_request：I/O 错误，dev sdc，...”等）
丢弃它或不再将其用于重要的事情。