Find kernel driver/module

sysconfig · New Member Joined: 12 Oct 2025 Posts: 23

To find out what a particular driver/module does you can usually use the modinfo command:

# modinfo -d e1000
Intel(R) PRO/1000 Network Driver
#
# modinfo -d hangcheck-timer
Hangcheck-timer detects when the system has gone out to lunch past a certain margin.
#

To get a list of parameters supported by a kernel driver/module, the modinfo command will usually provide the information:

# modinfo -p e1000
debug:Debug level (0=none,...,16=all)
InterruptThrottleRate:Interrupt Throttling Rate
RxAbsIntDelay:Receive Absolute Interrupt Delay
RxIntDelay:Receive Interrupt Delay
TxAbsIntDelay:Transmit Absolute Interrupt Delay
TxIntDelay:Transmit Interrupt Delay
XsumRX:Disable or enable Receive Checksum offload
FlowControl:Flow Control setting
AutoNeg:Advertised auto-negotiation setting
Duplex:Duplex setting
Speed:Speed setting
RxDescriptors:Number of receive descriptors
TxDescriptors:Number of transmit descriptors
#
# modinfo -p hangcheck-timer
hangcheck_dump_tasks:If nonzero, the machine will dump the system task state when the timer margin is exceeded.
hangcheck_reboot:If nonzero, the machine will reboot when the timer margin is exceeded.
hangcheck_margin:If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire.
hangcheck_tick:Timer delay.
#

To set the parameters when modules are loaded, you can add entries to /etc/modprobe.conf on RHEL or /etc/modprobe.conf.local on SLES. For example:

options hangcheck-timer hangcheck_tick=30 hangcheck_margin=180

To load the module and see the new settings, run:

# modprobe -v hangcheck-timer
insmod /lib/modules/2.6.9-22.EL/kernel/drivers/char/hangcheck-timer.ko hangcheck_tick=20 hangcheck_margin=280
#
# dmesg | tail -1
Hangcheck: starting hangcheck timer 0.5.0 (tick is 30 seconds, margin is 180 seconds).
#

The newly loaded module will be at the top of the lsmod list:

# lsmod | head -2
Module Size Used by
hangcheck_timer 3289 0
#

To unload the module, run:

# rmmod hangcheck-timer

thanks,

mkitwrk · Posted: Thu Mar 06, 2025 9:10 pm Post subject:

How does one fix the situation where modinfo cannot locate the driver module?
Here's the scenario and how I fixed it:

I run 'lsmod' and get (snip):
Module Size Used by
st 42912 0
bitblit 6208 0

And if I run 'modinfo st' I get (snip):
filename: /lib/modules/2.6.12/kernel/drivers/scsi/st.ko
author: Kai Makisara
description: SCSI Tape Driver
license: GPL
vermagic: 2.6.12 SMP 686 gcc-4.0

But, when I run 'modinfo bitblit' I get:
modinfo: could not find module bitblit

So, the answer is to run 'depmod' after saving your current modules.dep file... just in case...
And -- you have to log out and back in before bitblit can be found.
Here are the commands I used:

cd /lib/modules/[currentkernelversion]
cp modules.dep modules.dep.save
cd /
depmod
[Log off system]
[Log into system]
modinfo bitblit

And it shows:
filename: /lib/modules/2.6.12/kernel/drivers/video/console/bitblit.ko
author: Antonino Daplas <[email protected]>
description: Bit Blitting Operation
license: GPL
vermagic: 2.6.12 SMP 686 gcc-4.0

Enjoy!

_________________
Debian Sarge 32bit 2.4 kernel
Debian Etch 32&64bit 2.6 kernel
RedHat ES4 32bit 2.4 kernel
RedHat ES5 32&64bit 2.6 kernel
Old Caldera 2.2 kernel

JP · Posted: Fri Mar 07, 2025 12:50 am Post subject:

I think you probably should have put that into the "Command Line Commands" forum, so it will be easier to find when a person recollects the thread and goes looking for it Wink

. Thanks for the info!

mkitwrk Welcome to USALUG! Glad to have you aboard Very Happy

_________________
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