Finding out about drivers at runtime

Once you have a running Linux system, it is useful to know which device drivers are loaded and what state they are in. You can find out a lot by reading the files in /proc and /sys.

First of all, you can list the character and block device drivers currently loaded and active by reading /proc/devices:

# cat /proc/devices Character devices: 1 mem 2 pty 3 ttyp 4 /dev/vc/0 4 tty 4 ttyS 5 /dev/tty 5 /dev/console 5 /dev/ptmx 7 vcs 10 misc 13 input 29 fb 81 video4linux 89 i2c 90 mtd 116 alsa 128 ptm 136 pts 153 spi 180 usb 189 usb_device 204 ttySC 204 ttyAMA 207 ttymxc 226 drm 239 ttyLP 240 ttyTHS 241 ttySiRF 242 ttyPS 243 ttyWMT 244 ttyAS 245 ttyO 246 ttyMSM 247 ttyAML 248 bsg 249 iio 250 watchdog 251 ptp 252 pps 253 ...

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