我有一个嵌入式 Linux 设备，我试图将一些文件复制到其中。我插入 USB 记忆棒，dmesg 显示它已被识别，但由于某种原因/dev/sda1从未出现。
我试图了解发生了什么事......为什么/dev/sdaX根本没有出现，我该怎么办？
这是 dmesg：
[ 434.006104] usb 1-1: new full-speed USB device number 2 using musb-hdrc
[ 434.066132] hub 1-0:1.0: unable to enumerate USB device on port 1
[ 434.466078] usb 1-1: new high-speed USB device number 3 using musb-hdrc
[ 434.606941] usb 1-1: New USB device found, idVendor=14cd, idProduct=125c
[ 434.614008] usb 1-1: New USB device strings: Mfr=1, Product=3, SerialNumber=2
[ 434.621548] usb 1-1: Product: Mass Storage Device
[ 434.626512] usb 1-1: Manufacturer: Generic
[ 434.630825] usb 1-1: SerialNumber: 125C20100726
[ 434.637445] scsi0 : usb-storage 1-1:1.0
[ 435.636998] scsi 0:0:0:0: Direct-Access Mass Storage Device PQ: 0 ANSI: 0 CCS
[ 435.649935] sd 0:0:0:0: [sda] 15644672 512-byte logical blocks: (8.01 GB/7.45 GiB)
[ 435.658578] sd 0:0:0:0: [sda] Write Protect is off
[ 435.663874] sd 0:0:0:0: [sda] No Caching mode page present
[ 435.669696] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 435.678648] sd 0:0:0:0: [sda] No Caching mode page present
[ 435.684443] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 435.692168] sda: sda1
[ 435.697256] sd 0:0:0:0: [sda] No Caching mode page present
[ 435.703051] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 435.709499] sd 0:0:0:0: [sda] Attached SCSI removable disk
我检查了一下/proc/partitions，可以看到它在那里：
-sh-4.2# cat partitions
major minor #blocks name
31 0 128 mtdblock0
31 1 256 mtdblock1
31 2 64 mtdblock2
31 3 1408 mtdblock3
31 4 2560 mtdblock4
31 5 3776 mtdblock5
31 6 8192 mtdblock6
179 0 7822336 mmcblk0
179 1 72261 mmcblk0p1
179 2 7735297 mmcblk0p2
8 0 7822336 sda
8 1 7818240 sda1
这是 的快照/dev，如您所见，没有sda1：
-sh-4.2# ls /dev
Buzzer mem ram5 tty39
MAKEDEV mice ram6 tty4
XOR mmcblk0 ram7 tty40
apm_bios mmcblk0p1 ram8 tty41
console mmcblk0p2 ram9 tty42
core mouse0 ramdisk tty43
cpu_dma_latency mtd0 random tty44
crypto mtd0ro rfkill tty45
event0 mtd1 root tty46
fb0 mtd1ro rtc0 tty47
fd mtd2 stderr tty48
full mtd2ro stdin tty49
gpioLeds mtd3 stdout tty5
gpioOperate mtd3ro timer tty50
hda mtd4 tscadc-test tty51
hda1 mtd4ro tty tty52
hda10 mtd5 tty0 tty53
hda11 mtd5ro tty1 tty54
hda12 mtd6 tty10 tty55
hda13 mtd6ro tty11 tty56
hda14 mtd7 tty12 tty57
hda15 mtdblock0 tty13 tty58
hda16 mtdblock1 tty14 tty59
hda17 mtdblock2 tty15 tty6
hda18 mtdblock3 tty16 tty60
hda19 mtdblock4 tty17 tty61
hda2 mtdblock5 tty18 tty62
hda3 mtdblock6 tty19 tty63
hda4 mtdblock7 tty2 tty7
hda5 network_latency tty20 tty8
hda6 network_throughput tty21 tty9
hda7 nfsd tty22 ttyO0
hda8 null tty23 ttyO1
hda9 psaux tty24 ttyO2
hw_random ptmx tty25 ttyO3
i2c-1 pts tty26 ttyO4
initctl pvrsrvkm tty27 ttyS0
kmem ram tty28 ttySA0
kmsg ram0 tty29 ubi_ctrl
log ram1 tty3 urandom
loop-control ram10 tty30 usbdev1.1
loop0 ram11 tty31 vcs
loop1 ram12 tty32 vcs1
loop2 ram13 tty33 vcsa
loop3 ram14 tty34 vcsa1
loop4 ram15 tty35 zero
loop5 ram2 tty36
loop6 ram3 tty37
loop7 ram4 tty38
这udev monitor也是日志：
KERNEL[1431.270571] add /de[ 1431.278179] scsi1 : usb-storage 1-1:1.0
vices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1 (usb)
KERNEL[1431.271543] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0 (usb)
KERNEL[1431.277947] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1 (scsi)
KERNEL[1431.278561] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/scsi_host/host1 (scsi_host)
KERNEL[1431.280381] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/usb_device/usbdev1.6 (usb_device)
[ 1432.287008] scsi 1:0:0:0: Direct-Access Mass Storage Device PQ: 0 ANSI: 0 CCS
KERNEL[1432.291899] add /devices/platform/o[ 1432.301160] sd 1:0:0:0: [sda] 15644672 512-byte logical blocks: (8.01 GB/7.45 GiB)
map/musb-ti81xx/[ 1432.310858] sd 1:0:0:0: [sda] Write Protect is off
musb-hdrc.1/usb1[ 1432.317254] sd 1:0:0:0: [sda] No Caching mode page present
/1-1/1-1:1.0/hos[ 1432.323863] sd 1:0:0:0: [sda] Assuming drive cache: write through
t1/target1:0:0 (scsi)
KERNEL[14[ 1432.334323] sd 1:0:0:0: [sda] No Caching mode page present
32.292637] add [ 1432.340312] sd 1:0:0:0: [sda] Assuming drive cache: write through
/devices/platform/omap/musb-[ 1432.349590] sda: sda1
ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/target[ 1432.356659] sd 1:0:0:0: [sda] No Caching mode page present
1:0:0/1:0:0:0 (s[ 1432.363347] sd 1:0:0:0: [sda] Assuming drive cache: write through
csi)
KERNEL[143[ 1432.371188] sd 1:0:0:0: [sda] Attached SCSI removable disk
2.293192] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/target1:0:0/1:0:0:0/scsi_disk/1:0:0:0 (scsi_disk)
KERNEL[1432.293657] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/target1:0:0/1:0:0:0/scsi_device/1:0:0:0 (scsi_device)
KERNEL[1432.326141] add /devices/virtual/bdi/8:0 (bdi)
KERNEL[1432.347981] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/target1:0:0/1:0:0:0/block/sda (block)
KERNEL[1432.348571] add /devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.0/host1/target1:0:0/1:0:0:0/block/sda/sda1 (block)
答案1
好吧，我刚刚找到了问题的一半答案：
……我能做什么呢？
显然我可以自己制作设备节点。我将 U 盘插入我的笔记本电脑，发现它枚举为：
brw-rw---- 1 root disk 8, 0 Apr 3 13:15 /dev/sda
brw-rw---- 1 root disk 8, 1 Apr 3 13:15 /dev/sda1
因此，块设备的主版本号为 8，次版本号为 0 和 1。我检查了嵌入式设备上的长列表/dev，发现没有其他设备使用主版本号 8，因此我手动创建了节点：
-sh-4.2# mknod /dev/sda b 8 0
-sh-4.2# mknod /dev/sda1 b 8 1
然后我创建了一个目录并将新的 sda1 安装到该目录：
-sh-4.2# cd /mnt/
-sh-4.2# mkdir usbdrive
-sh-4.2# mount /dev/sda1 /mnt/usbdrive/
-sh-4.2# ls /mnt/usbdrive/
libEGL.so libsrv_um.so
现在我可以看到 USB 驱动器的内容了。这就回答了“我能做什么”。我仍然有一个问题，为什么我需要在嵌入式板上手动执行此操作。一定有什么东西......也许在 USB 驱动程序中，可以自动完成这一切。