In section 08, how to configure kernel after making changes?
In section 8: writing your first patch,
I made the change to the uvc_driver.c by adding the following line
pr_info("I changed uvcvideo driver in the Linux Kernel\n");
Now how do I configure the module CONFIG_USB_VIDEO_CLASS=y?
I manually changed the line in .config from 'm' to 'y' and recompiled the kernel using:
make -j3 all
But I don't see the change in dmesg and now I am stuck in this part.
Best Answer
-
Sorry I didn't know other alternative, but really not suggest to edit
.config
file directly, as the file itself said, "Automatically generated file; DO NOT EDIT."You can search by
/
in the menu, for example,/USB_VIDEO_CLASS
says the dependency tree
--Device Drivers
--MEDIA_SUPPORT
--MEDIA_USB_SUPPORT
--USB_VIDEO_CLASS
So in this case, single change ofUSB_VIDEO_CLASS
expect to work. But in general case, change(especially add) a single entry in.config
file may leave it's dependency wild.By the way,
y
(built-in to kernel image) andm
(build as a module) controls how to build the module into the new image. Butsudo modprobe uvcvideo
searches modules in the current operating system, I guess that's why it works after reboot.
Have you tried toinsmod
after make (set it asm
), hope it can save you from an extra reboot.0
Answers
-
Edit: After make -j3 I followed the rest of the instructions:
sudo make modules_install install
sudo modprobe uvcvideo
dmesg | less | grep "changed"And I dint see any result!
0 -
Update: It seems to work ONLY IF I reboot my system but the course material says I don't need to reboot. Please tell me where I went wrong with my commands? This is the list of commands I executed:
- vim .config # to change CONFIG_USB_VIDEO_CLASS from 'm' to 'y'
- make -j6
- sudo make modules_install install
- sudo modprobe uvcvideo
- dmesg | less | grep "changed" # didn't work
- sudo reboot
- dmesg | less | grep "changed" # works now!
Where did I go wrong?
0 -
@amoghmc said:
In section 8: writing your first patch,
I made the change to the uvc_driver.c by adding the following linepr_info("I changed uvcvideo driver in the Linux Kernel\n");
Now how do I configure the module CONFIG_USB_VIDEO_CLASS=y?
I would try
make menuconfig
I manually changed the line in .config from 'm' to 'y' and recompiled the kernel using:
Suggest not to do that way,
reason 1: change .config file directly may leave some dependencies untouched.
reason 2: change fromm
toy
has nothing to do with this issue.make -j3 all
after this, you will have a ko file named like uvc.ko, insmod that ko
But I don't see the change in dmesg and now I am stuck in this part.
1 -
Hi amoghmc,
Changing .config file manually is not a good idea. You may miss dependencies (if any).0 -
Hey, I just encountered the same thing.
All you have to do it update grub and boot into the "dirty" version.
I realized that after running
ll /boot
and noticing that the most up to date image has no longer the original name.Simply put: you have to boot into the most up to date version of your Kernel:
0
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