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I'm building my own Embedded Linux distro using bitbake . I added udev in the list of dependencies (RDEPENDS).

I noticed that the output of:

udevadm info --query=property --path=/sys/block/sda

is just:

DEVNAME=/dev/sda
DEVPATH=/devices/pci0000:00/0000:00:13.0/ata1/host0/target0:0:0/0:0:0:0/block/sda
DEVTYPE=disk
MAJOR=8
MINOR=0
SUBSYSTEM=block

whereas I expect something like this (the output on my Ubuntu):

DEVLINKS=/dev/disk/by-id/ata-WDC_WD10EALX-009BA0_WD-WMATR1360774 /dev/disk/by-id/wwn-0x50014ee2072ca983
DEVNAME=/dev/sda
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/block/sda
DEVTYPE=disk
ID_ATA=1
ID_ATA_DOWNLOAD_MICROCODE=1
ID_ATA_FEATURE_SET_HPA=1
ID_ATA_FEATURE_SET_HPA_ENABLED=1
ID_ATA_FEATURE_SET_PM=1
ID_ATA_FEATURE_SET_PM_ENABLED=1
ID_ATA_FEATURE_SET_PUIS=1
ID_ATA_FEATURE_SET_PUIS_ENABLED=0
ID_ATA_FEATURE_SET_SECURITY=1
ID_ATA_FEATURE_SET_SECURITY_ENABLED=0
ID_ATA_FEATURE_SET_SECURITY_ENHANCED_ERASE_UNIT_MIN=174
ID_ATA_FEATURE_SET_SECURITY_ERASE_UNIT_MIN=174
ID_ATA_FEATURE_SET_SECURITY_FROZEN=1
ID_ATA_FEATURE_SET_SMART=1
ID_ATA_FEATURE_SET_SMART_ENABLED=1
ID_ATA_SATA=1
ID_ATA_SATA_SIGNAL_RATE_GEN1=1
ID_ATA_SATA_SIGNAL_RATE_GEN2=1
ID_ATA_WRITE_CACHE=1
ID_ATA_WRITE_CACHE_ENABLED=1
ID_BUS=ata
ID_MODEL=WDC_WD10EALX-009BA0
ID_MODEL_ENC=WDC\x20WD10EALX-009BA0\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20
ID_PART_TABLE_TYPE=dos
ID_REVISION=15.01H15
ID_SERIAL=WDC_WD10EALX-009BA0_WD-WMATR1360774
ID_SERIAL_SHORT=WD-WMATR1360774
ID_TYPE=disk
ID_WWN=0x50014ee2072ca983
ID_WWN_WITH_EXTENSION=0x50014ee2072ca983
MAJOR=8
MINOR=0
SUBSYSTEM=block

I want to grep after ID_BUS to check whether a device is a usb or not, but it seems that the lines ID_ are missing.

Do you know what am I missing here? My first guess is a missing package, which I am not aware of. Thank you.

0

The problem is that udev was not started.

/etc/init.d/udev start

Conclusion: in case someone experiences any issue related to udev, firstly make sure it has been started.

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