我有一台 Acer Aspire One 522 上网本，我想让 SD 卡读卡器正常工作，但在插入 SD 卡后我无法让它识别它。
我使用 Slackware 并总是编译自己的内核，因此我已经启用了该Device Drivers->MMC/SD/SDIO card support选项和相应的内核模块，编译并正确安装了内核及其模块（内核版本为 3.5.3）。
一旦插入 SD 卡，读卡器似乎就会连接到 USB 总线，因为lsusb仅在此事件后显示读卡器：
Bus 002 Device 005: ID 0cf2:6250 ENE Technology, Inc. SD card reader (UB6250)
我通常希望在插入卡后看到像块设备/dev/mmcblk0和卡分区（/dev/mmcblk0p1等/dev/mmcblk0p2），但什么也没有显示。插入卡时监视 /var/log/messages 显示以下内容：
Sep 8 14:43:41 aspire kernel: usb 2-2: USB disconnect, device number 5
Sep 8 14:43:44 aspire kernel: usb 2-2: new high-speed USB device number 6 using ehci_hcd
Sep 8 14:43:44 aspire kernel: usb 2-2: New USB device found, idVendor=0cf2, idProduct=6250
Sep 8 14:43:44 aspire kernel: usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=4
Sep 8 14:43:44 aspire kernel: usb 2-2: Product: UB6250
Sep 8 14:43:44 aspire kernel: usb 2-2: Manufacturer: ENE Flash
Sep 8 14:43:44 aspire kernel: usb 2-2: SerialNumber: 606569746801
Sep 8 14:43:44 aspire mtp-probe: checking bus 2, device 6: "/sys/devices/pci0000:00/0000:00:13.2/usb2/2-2"
Sep 8 14:43:44 aspire mtp-probe: bus: 2, device: 6 was not an MTP device
显示读卡器已连接到 USB 总线，但未检测到块设备。有人对此有任何提示吗？我是否错过了某些内容或对该阅读器的支持尚未完全发挥作用？谢谢！
答案1
在通用 Slackware 内核上重新启动后，我注意到 SD 卡被检测为 SCSI 设备 - dmesg 输出如下：
[ 205.694553] usb 2-2: new high-speed USB device number 3 using ehci_hcd
[ 205.812086] usb 2-2: New USB device found, idVendor=0cf2, idProduct=6250
[ 205.812100] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=4
[ 205.812109] usb 2-2: Product: UB6250
[ 205.812116] usb 2-2: Manufacturer: ENE Flash
[ 205.812122] usb 2-2: SerialNumber: 606569746801
[ 205.841074] scsi3 : usb-storage 2-2:1.0
[ 205.842222] usbcore: registered new interface driver ums_eneub6250
[ 205.848453] keucr: module is from the staging directory, the quality is unknown, you have been warned.
[ 205.850027] usb --- usb_stor_init start
[ 205.850103] usbcore: registered new interface driver eucr
[ 205.850109] ENE USB Mass Storage support registered.
[ 207.175693] scsi scan: INQUIRY result too short (5), using 36
[ 207.175714] scsi 3:0:0:0: Direct-Access PQ: 0 ANSI: 0
[ 207.177069] sd 3:0:0:0: [sdb] 3911680 512-byte logical blocks: (2.00 GB/1.86 GiB)
[ 207.177250] sd 3:0:0:0: [sdb] Write Protect is off
[ 207.177262] sd 3:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[ 207.177437] sd 3:0:0:0: [sdb] No Caching mode page present
[ 207.177445] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[ 207.179216] sd 3:0:0:0: [sdb] No Caching mode page present
[ 207.179230] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[ 207.208861] sdb: sdb1 sdb2 sdb3
[ 207.209959] sd 3:0:0:0: [sdb] No Caching mode page present
[ 207.209971] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[ 207.209980] sd 3:0:0:0: [sdb] Attached SCSI disk
该行ENE USB Mass Storage support registered暗示缺少与 USB 支持相关的内容，因此我发现此选项已关闭：Device Drivers->USB Support->USB ENE card reader support。重新编译包含此模块的内核后，可以像往常一样通过关联的 SCSI 块设备访问 SD 卡。