Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up.
Sign up to join this community
As the question says it all, I would just like to elaborate with an example:
i915.i915_enable_rc6=1
This is an option for i915 module or intel video driver. So is there any way to know or list something like i915_enable_rc6 is an option for i915 from linux commandline ?
I hope I am clear with the question ?
Edit: I was referring to i915 just for example and nothing else. modinfo seems to be the command I was looking for.
modinfo does it:
modinfo i915 | grep '^parm:'
For open source modules the most reliable way is to look at the source. You don't need to be a kernel developer.
See source for i915.
parm in the modinfo output does that mean there is no options to configure the modules?
Aug 30, 2011 at 9:37
You can find all the applicable i915 kernel params applicable for your card using a command such as
sudo grep -H '' /sys/module/i915/parameters/*
or
sudo grep . /sys/module/i915/parameters/*
(thanks @arrange)
In my case I can potentially use:
/sys/module/i915/parameters/fbpercrtc:0
/sys/module/i915/parameters/i915_enable_rc6:1
/sys/module/i915/parameters/lvds_downclock:1
/sys/module/i915/parameters/lvds_use_ssc:1
/sys/module/i915/parameters/modeset:-1
/sys/module/i915/parameters/powersave:1
/sys/module/i915/parameters/reset:Y
/sys/module/i915/parameters/semaphores:0
If no parameters are identified then either that is a true statement - or the kernel is loading a different kernel module than you were expecting:
sudo lshw -c display
*-display
description: VGA compatible controller
product: Core Processor Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 18
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:41 memory:90000000-903fffff memory:80000000-8fffffff ioport:3050(size=8)
In the above trace you can see in the configuration line "driver=i915" that the kernel sees the video card and has loaded the i915 module.
sudo grep . /sys/module/i915/parameters/*
i915 because its mostly used. But the path information was something I didn't know, so if there is no parameters folder in the /sys/module/{module_name}/ Does that mean the specific module doesnot have options to tweak ?
Aug 30, 2011 at 4:23
Perhaps this is an newer modinfo options, but modinfo support listing only the parameters:
$ modinfo -p i915
or
$ modinfo --parameters i915
Note: the $ sign is just the prompt display. It shows that the command can be run as a non-root user and without sudo.
It is possible to also check the current parameters of an already loaded modules using systool:
systool is part of the sysfsutils package. Install it with this command
sudo apt-get install sysfsutils
Then use it this way
$ systool -v -m i915
In the output of this command check the "Parameters:" section.
