May 2020 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

What is the minimal set of firmware files I need for my hardware?
by Doron Behar May 4, 2020

May 4, 2020

I hope this question fits to this List. Today I learned that my distro's `linux-unfree-firmware` package is 491 Mb in size. I'm pretty sure my hardware doesn't need all of these files. Maybe different Linux distros call this package differently, but I'm talking about the firmware files that come from: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/ I think I can reduce this disk usage if I'll only know what files I can exclude from there. Is there any official documentation, that states exactly what files from That git repo are needed per device / computer model? Perhaps the official documentation of my Computer's hardware will state that? There's a Linux from scratch webpage[1] that gives some info for popular hardware, but I'm wondering if there's a bit more "official" information available somewhere. [1]: http://linuxfromscratch.org/blfs/view/svn/postlfs/firmware.html Thanks.

2 4

Would .DTSIs without DTS be accepted into the kernel?
by Dávid Virág May 4, 2020

May 4, 2020

Hi, I have an Android phone that I'd like to see running on the mainline kernel one day. Currently it runs a downstream 4.4 kernel. Since the stock (closed source) bootloader on the phone only really checks the SOC in a property in the DTBs but not the model of the phone, I'm sure a DTS for the phone wouldn't be accepted in the kernel, because it would match other devices with the same SOC. My question is this: Would DTSIs for it's SOC, and its components be merged without any DTS actually including them? That way if the phone would ever get a more proper bootloader for it that checks the model properly, the only thing that would need to be done is just making a DTS with the correct compatible property in it, and until then if someone would want to run it on his phone, the diff between the fork they would need to use and upstream would just be the DTS. Thanks, David

3 3

Reg : signature and/or required key missing
by Majji SankaraRao May 4, 2020

May 4, 2020

Hi, I got the following kernel message after inserting my sample char dev module into kernel version - 5.3.0-51-generic *[17866.747927] mychardev: module verification failed: signature and/or required key missing - tainting kernel* Please guide me how to solve this issue. Thanks in advance, Sankara Rao Majji

2 1

Re: Reg : Writing modules in new Linux versions
by Majji SankaraRao May 4, 2020

May 4, 2020

Hi, Please suggest some IDE's to Linux code navigation and development if possible. Thanks in advance, Sankara Rao Majji On Sun, May 3, 2020 at 10:49 AM Majji SankaraRao < sankar.linux.development(a)gmail.com> wrote: > Hi Valdis, > > Thanks for your reply. > > With your suggestions I have used the following code to test helloworld > module and successfully saw "Hello World!' msg with dmesg command. > > #include<linux/module.h> > #include<linux/init.h> > #include<linux/kernel.h> > > > MODULE_LICENSE("GPL"); > MODULE_AUTHOR("Sankar"); > MODULE_DESCRIPTION("Hello World Module"); > > static int __init helloworld_init(void) > { > printk(KERN_INFO "Hello world!\n"); > return 0; > } > > static void __exit helloworld_exit(void) > { > printk(KERN_INFO "Cleaning up module.\n"); > return; > } > > module_init(helloworld_init); > module_exit(helloworld_exit); > > > BR, > Sankar > > On Sun, May 3, 2020 at 1:37 AM Valdis Klētnieks <valdis.kletnieks(a)vt.edu> > wrote: > >> On Sat, 02 May 2020 23:46:08 +0530, Majji SankaraRao said: >> >> > I want to practice writing modules in Linux version 5.3.0-51-generic. >> > So please guide me by providing related documentation/Steps. >> >> Create two functions, one for initializing your module, and one for >> cleaning up at exit. >> >> static int __init init_my_module(void) >> { >> printk(KERN_DEBUG "Hello World!\n"); >> } >> >> static void __exit exit_my_module(void) >> { >> printk(KERN_DEBUG "Say goodnight, Gracie\n"); >> } >> module_init(init_my_module); >> module_exit(exit_my_module); >> >> Everything else isn't how to write a module, it's about how to write >> whatever >> code is needed for the function you're trying to add, whether it's a file >> system, or a new netfilter target, or a device driver, or a network >> congestion >> control module, or whatever... >> >> And that code basically doesn't care if it's a module or if it's built in >> to >> the kernel. >> >> So the question becomes: What did you want to do inside the kernel? >> >

2 1

Getting started on writing a driver for the rpi4
by Jacko Dirks May 4, 2020

May 4, 2020

Hello all, I want to get started on writing a driver for the I2C slave for the Raspberry Pi 4. Now, I have a feeling that I cannot just write the thing and then dump it on everyone involved, not in the last place because I have never submitted a kernel patch before. So, should I email a mailing list warning everyone of what I want to do? Is there anything else I should know about? To clarify, this is not about the creation of the driver itself, more of a meta question of how to announce that I want to do this. Thanks in advance, Jacko Dirks

2 1

SElinux and its own error code?
by Jeffrey Walton May 3, 2020

May 3, 2020

Hi Guys, I lost about four hours chasing inaccurate messages from Apache. It turns out SElinux was denying access, so the EPERM was not really accurate. But Apache saw EPERM or EACCESS and logged a message related to Posix permissions. As far as I know Posix does not authorize use of EPERM or EACCESS for SElinux. That is, SElinux should not be hijacking the error code. I'm wondering why there is no error message for SElinux that would allow application to return a specific error when SElinux denies access to an object or operation. Why does SElinux not have its own error code?

4 5

Reg : Writing modules in new Linux versions
by Majji SankaraRao May 2, 2020

May 2, 2020

Hi All, I want to practice writing modules in Linux version 5.3.0-51-generic. So please guide me by providing related documentation/Steps. Thanks in advance, SankaraRao Majji

2 1

Kernel janitors discussion list
by hemanth nandish May 1, 2020

May 1, 2020

Hi, I came across the Kernel Janitors page for beginners looking to contribute. The TODO list under kernel janitors guides you on what could be done rather than specifically discussing any issues. So I wanted to know if there is any discussion list on what tasks are waiting to be completed. Thank you, Hemanth

2 1

LDD3 vs Essential Linux Device Drivers
by Mohamed Dawod May 1, 2020

May 1, 2020

Hi, I would like to start learning about Linux kernel and device drivers development. Should I have to start with LDD3 as a lot of people advice ? or can I start with the Essential Linux Device Drivers by Sreekrishnan Venkateswaran. I know that the second book may be more advanced but I feel that it's more more practical and easier to be understood. Thanks, -- Mohamed

3 4