我在自訂 Linux 核心中遇到 USB 隨身碟寫入速度慢的問題。我懷疑是硬體問題，但在相同的硬體和 Opensuse 12.1 作業系統下，我的 USB 隨身碟的寫入速度要快得多。
我還觀察到，當我的 USB 隨身碟插入 OpenSuse 12.1 和我的自訂核心時，dmesg 輸出有顯著差異。
OpenSuse12.1 中的 dmesg
[ 665.417077] usb 2-2: USB disconnect, device number 4
[ 668.676014] usb 2-2: new high speed USB device number 5 using ehci_hcd
[ 668.812675] usb 2-2: New USB device found, idVendor=0815, idProduct=2002
[ 668.812679] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 668.812682] usb 2-2: Product: USBInstallMedia
[ 668.812685] usb 2-2: Manufacturer:
[ 668.812687] usb 2-2: SerialNumber: 070B49D39981F580
[ 668.813052] scsi7 : usb-storage 2-2:1.0
[ 669.813701] scsi 7:0:0:0: Direct-Access USBDrive PMAP PQ: 0 ANSI: 6
[ 669.813893] sd 7:0:0:0: Attached scsi generic sg2 type 0
[ 670.912190] sd 7:0:0:0: [sdc] 62554112 512-byte logical blocks: (32.0 GB/29.8 GiB)
[ 670.913182] sd 7:0:0:0: [sdc] Write Protect is off
[ 670.913186] sd 7:0:0:0: [sdc] Mode Sense: 23 00 00 00
[ 670.914181] sd 7:0:0:0: [sdc] No Caching mode page present
[ 670.914185] sd 7:0:0:0: [sdc] Assuming drive cache: write through
[ 670.918180] sd 7:0:0:0: [sdc] No Caching mode page present
[ 670.918184] sd 7:0:0:0: [sdc] Assuming drive cache: write through
[ 670.919112] sdc: sdc1
[ 670.923056] sd 7:0:0:0: [sdc] No Caching mode page present
[ 670.923060] sd 7:0:0:0: [sdc] Assuming drive cache: write through
[ 670.923063] sd 7:0:0:0: [sdc] Attached SCSI removable disk
我的自訂內核中的 dmesg：
usb 2-1: new high speed USB device number 3 using ehci_hcd
usb 2-1: New USB device found, idVendor=0815, idProduct=2002
usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1: Product: USBDrive
usb 2-1: Manufacturer:
usb 2-1: SerialNumber: 070B49D39981F580
ubb: ubb1
從 dmesg 輸出來看，我的 USB 設備在 OpenSuse 12.1 中被識別為 scsi 設備，而在我的自訂內核中，它不被識別為 scsi 設備。
我懷疑這可能是我的自訂內核寫入速度慢的可能原因。
如果我希望我的 USB 設備被識別為 scsi 設備，我是否需要啟用任何核心配置？如果是的話，如果有人能指出我應該修改哪些核心配置，那將會很有幫助。謝謝。