Can two devices have the same major and minor number?

david_8274 · 04-30-2014, 08:05 PM

Hi,

I have created two devices /dev/rtc0 and /dev/rtc1. Just for fun I let them have the same major AND minor number, and they seem to work fine. As I understand the minor number should be different for two different devices using the same driver. Am I mistaken?

Thanks,
Wei

kbp · 04-30-2014, 08:12 PM

You're not mistaken but what you may find is that you are only accessing one of the devices not both.

Ser Olmy · 04-30-2014, 08:15 PM

A device node is just a pointer to a kernel resource with a certain major and minor number. The major/minor combination decides which device you end up accessing, not the name of the device node.

You can have any number of device nodes pointing to the same device.