linux kernel - Understanding dmesg messages -


i newbie learning how write linux device drivers usb devices. want understand dmesg ouput

[ 6870.420077] usb 2-5: new low-speed usb device number 43 using ohci_hcd [ 6870.500057] hub 2-0:1.0: unable enumerate usb device on port 5 [ 6871.444057] usb 2-5: new low-speed usb device number 44 using ohci_hcd [ 6871.524065] hub 2-0:1.0: unable enumerate usb device on port 5 [ 6872.468089] usb 2-5: new low-speed usb device number 45 using ohci_hcd [ 6872.548065] hub 2-0:1.0: unable enumerate usb device on port 5

could direct me reading material explaining how decipher these kernel messages?

dmesg - print or control kernel ring buffer.

when dmesg command issued, kernel ring buffer messages printed. there no specific format used guess.

mostly whenever new driver(or kernel code) written, particular module name print first , corresponding message printed differentiating our messages.

for example,

printk(kern_alert "jaymodule: module loaded successfully.. ");

will print jaymodule: module loaded successfully.. in kernel ring buffer.

i guess numeric values given within [] time.


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