Everything about UNIX kernels: development, configuration, compilation, design, etc.

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4
votes
2answers
788 views

Benefiting of sched_autogroup_enabled on the desktop

I am running a 2.6.37 kernel with sched_autogroup_enabled set to 1. I am not certain that I am seeing the benefits of this patch since: I am launching my applications from the desktop; applications ...
1
vote
0answers
7 views

Error compiling buildroot

i updated my buildroot for the version "2014.08" (stable version) and i updated the Kernel version (3.12.26) of my project, when the buildroot try to build the "linux-headers-3.12.26" package, occurs ...
16
votes
3answers
155 views

How did the Linux Kernel project track bugs in the Early Days?

We all know that Linus Torvalds created Git because of issues with Bitkeeper. What is not known (at least to me) is, how were issues/tickets/bugs tracked up until then? I tried but didn't get anything ...
1
vote
2answers
964 views

“select” vs “depends” in kernel Kconfig

What are the differences in dependencies between select and depends on in the kernels Kconfig files? config FB_CIRRUS tristate "Cirrus Logic support" depends on FB && (ZORRO || PCI) select ...
4
votes
1answer
1k views

Setting up HDMI output from Linux console

I am currently running Debian Wheezy on a HP Microserver N54L with an AMD Radeon 5450 video card. I would like to be able to play audio from the console through the HDMI port of my video card and ...
2
votes
0answers
54 views
+100

Why will plymouth not update?

I admit I don't update my kernel very often. I used to everytime a stable release of sys-kernel/gentoo-sources came out so I'm very adept at doing it. This last weekend I attempted to update from ...
1
vote
2answers
871 views

running kernel on QEMU

I face this message: Failed to execute /initKernel panic - not syncing: no init found. Try passing init=option to kernel. I am using this command line: qemu-system-x86_64 -hda disk.img -kernel ...
1
vote
0answers
19 views

What exactly does struct nfs_unlinkdata do?

I been reading the source code of unlink() but i am stuck on nfs_unlinkdata and i can't find anything on it on the web. Thanks a lot for your help.
1
vote
0answers
22 views

HD 4800 lower fan speed

I've installed Linux Mint 17, most important thing for me is to lower the fan speed to 30% as I am doing in Windows because it's really too noisy. Note that the temperature stays at ~50°, so this ...
0
votes
2answers
28 views

Fatal error: linux/smp_lock.h: no such file or directory when trying to compile tiusb

I am trying to compile the TI-Graph Link USB Drivers? So I downloaded it, and ran make in the directory libusb. It produced the following: ~/Téléchargements/tiusb/tiusb-1.10$ make make -C ...
2
votes
1answer
905 views

How to get ondemand governor on fedora

In Ubuntu 13.10 on my (Dual Core i5 Lenovo G570) laptop, I recently discovered the wonders of indicator-cpufreq, so I can extend my battery life dramatically by setting it to 'ondemand' or 'powersave' ...
1
vote
0answers
22 views

real time kernel / low latency comes from the vanilla source

Does the vanilla source provide real time / low latency functionality ?
1
vote
1answer
3k views

How to get back from “testing” to “stable” - Kernel downgrade

currently I am having lot's of fun with apt-get - and the bad thing is, it was my own fault. I had enabled the testing packages in /etc/apt/sources.list to install a certain package. And I told my ...
3
votes
0answers
21 views

NTPD Nanokernel

I had a couple of questions about the NTP Nanokernel as explained here: http://www.eecis.udel.edu/~mills/database/brief/nano/nano.pdf The big question is how does this Nanokernel manage to deliver an ...
0
votes
1answer
19 views

module prints to kernel log with delay

I've created a basic linux kernel module, which does the following: static __init int init(void) { printk(KERN_DEBUG "Banana"); return 0; } And of course: module_init(init); Strangely, I ...
1
vote
1answer
430 views

Why system call hooking produces different result everytime in Linux/Android 2.6.29?

I have implemented system call hooking for Android 2.6.29 kernel through a LKM module. I am tracing down one Android app for system calls. But interestingly, it returns different results every time I ...
2
votes
1answer
45 views

Does each network packet cause an interrupt to CPU?

While I know that lot of packet processing(CRC calculations, packet segmentation handling, etc) can be offloaded to NIC, then does each packet still cause an interrupt to CPU? Is there a difference if ...
1
vote
0answers
14 views

ifup wlan0 causes kernel Oops

on my laptop, when I do ifup wlan0, sometimes I get following call trace in dmesg. Other times, the log looks perfectly normal, and there are no kernel Oops messages. In both cases (with errors and ...
0
votes
1answer
123 views

Questions about behaviour of running LiveCD Linux after unmounting a CD-ROM

Could anyone explain what happens in system after unplugging CD-ROM during working with LiveCD session? Suppose that I'm using Ubuntu LiveCD and suddenly by accident the CD-ROM disconnect for a ...
2
votes
1answer
696 views

How to Find and reload specific driver from kernel?

I am using Crunchbang 64 bit O.S. with a ASUS N150 wireless adapter. Everytime I close my laptop and it enters sleep mode, when I "wake it up" I am unable to connect back using the wireless adapter, I ...
0
votes
1answer
20 views

Changing linux config from 32 bit to 64 bit loses RTC

I have a config from a 32-bit linux 3.12.18, and was trying to compile a 64 bit version with most settings like selected drivers etc. the same as in 32 bit version. For this I used make menuconfig ...
0
votes
0answers
31 views

latest arch linux on beaglebone black

I have installed arch linux using what I assumed was the latest kernel at http://archlinuxarm.org/os/ArchLinuxARM-am33x-latest.tar.gz But this only installs 3.8.13 and I understand that there are ...
0
votes
0answers
23 views

Changing CPU frequency programmatically

I have seen that standard CPU Frequency driver(comes with default package with linux kernel) can change the CPU frequency at runtime, when being used under the supervision of "Ondemand" governor. ...
3
votes
1answer
176 views

Turning off power to usb port. Or turn off power to entire usb subsystem

I have a usb lamp which I specifically bought in order to turn it off programmatically at a certain time, thus I need to remove the power to its usb port. I believe I have a usb-hub at usb6. The lamp ...
0
votes
0answers
8 views

How to add new systemcall in Linux 3.2.x? [migrated]

I'm new to Linux, and I want to compile my kernel for Debian-amd64 with a new system call. The only tutorial I could find online was for a i386 or x86 system. I followed their instructions but at the ...
0
votes
0answers
160 views

FreeBSD boot problem, UEFI or LEGACY and GPT disk

i have a computer based on GPT disks with triple boot. For the moment i have two OSes working on my computer (OSX and Windows). I want to make a FreeBSD installation, he work perfectly when i boot on ...
6
votes
2answers
721 views

Asus X101H - Touchpad not recognized (want to disable while typing)

I have been struggling with this issue for a while and have done an exhaustive search for answers here and elsewhere before posting this question. On my Asus X101H, the touchpad is not recognized as ...
12
votes
2answers
769 views

memory limit of the Linux kernel

I have a perplexing problem. I have a library which uses sg for executing customized CDBs. There are a couple of systems which routinely have issues with memory allocation in sg. Usually, the sg ...
3
votes
2answers
2k views

Does Linux log when a process is started, and the PID that gets assigned to it? Where can I find that log?

When my Ubuntu server starts up, I see a message that says: kernel: [11.895392] init: failsafe main process (631) killed by TERM signal. I would like to know what process this is but I'm not sure ...
5
votes
1answer
114 views

Calls to sync/fsync slow down after 30 minutes uptime

After 30 minutes of uptime using Ubuntu 14.04 with a hybrid SSD I see many processes blocking IO using iotop. This is during disk writes, for example if I open and close an empty file in gedit it can ...
0
votes
1answer
2k views

bnx2: Can't load firmware file “bnx2/bnx2-mips-09-6.2.1b.fw”

I just compile the kernel 3.10.19 from kernel.org Support for bnx2 is enable. On my server when I try to start the eth0 interface I got the following error : bnx2: Can't load firmware file ...
1
vote
1answer
71 views

Kernel 3.14 not working with ATIProprietary fglrx?

On my debian laptop I installed kernel 3.14 so I have the alx driver so my ethernet works, I originally had the 3.2 kernel (Debian 7.7). AFter installing the new kernel, gnome3 went back to the ...
1
vote
1answer
32 views

Walk-through into make (menu)config's options [closed]

I need to customize the kernel a lot for a custom system. Most of my changes concern the kernel's memory usage (something like an embedded kernel). There are a lot of things enabled by default in the ...
2
votes
2answers
895 views

busybox initramfs loop mount

I'm trying to loop mount my root filesystem (a loop file) within a busybox initramfs. I try to run the command: mount /rootfs.raw /root ... which works on my Ubuntu laptop, however, I simply get ...
3
votes
2answers
442 views

Why CONFIG_NO_HZ is not set by default

In the Linux Kernel CONFIG_NO_HZ is not set. But an initial reading suggests that setting that option would be nice from a performance point of view. But reading some posts like this made me think ...
3
votes
1answer
978 views

Kernel booting stops right after “Uncompressing Linux…”

I'm trying to bring up an ARM-based board. I've got U-Boot working but can't seem to get the kernel to load. Most of the time it only goes as far as: Starting kernel ... Uncompressing Linux... A ...
1
vote
0answers
28 views

How to suppress input overrun messages

I have a Raspberry Pi running Raspbian (a Debian flavor: Linux version 3.12-1-rpi (debian-kernel@lists.debian.org) (gcc version 4.7.2 (Debian 4.7.2-5+rpi1) ) #1 Debian 3.12.9-1+rpi1 (2014-05-19) ). ...
1
vote
0answers
28 views

can't filter printk messages

I'm writing a driver and usually I implement my own log-level scheme. However, this time I figured that I would try to utilize the printk scheme that is built into Linux. I see that I can adjust the ...
2
votes
0answers
31 views

Where is located syscall_table in kernel x86_64? [migrated]

I'm trying to add new System Call to Linux Kernel(x86_64). Based on this article which explained how to add System Call to Kernel(x86). The article says I need to define my System Call name in a file ...
0
votes
0answers
13 views

How does setting the PE flag in CR0 enable protected mode? [migrated]

I am trying to understand how a machine goes from power on to running a kernel. From what I've gathered, it is useful to switch into protected mode during boot up in order to gain access to more ...
0
votes
1answer
95 views

IPTABLES comment: No chain/target/match by that name

Faced with error when adding new rule with 'comment': # iptables -I INPUT 1 --source 66.***.***.78 -j REJECT -m comment --comment "Some" iptables: No chain/target/match by that name. Without ...
1
vote
1answer
101 views

Full UEFI System, Grub 2 self-compiled + Clover 2, Debian kFreeBSD installation?

I've a computer with full installation UEFI system, with 2 bootloaders (GRUB & Clover on ESP) clover is the primary bootloader that allows me to load OSX and grub2. I want to make a new install of ...
1
vote
0answers
32 views

open() sys call [closed]

Process A wants to open a file fd1 = open("/var/file1", O_RDONLY); In the process of opening file1 which table is referred first system wide file table or file descriptor table or in-core inode ...
0
votes
0answers
21 views

How can I compile and run a program designed for an older kernel version (2.6) in a newer kernel (3.16)?

I'm trying to run a driver for a network card, but it only supports kernels up to 2.6.32. I need to be able to use this piece of hardware to connect to the Internet. The device I'm using is "VIA ...
12
votes
3answers
12k views

disable transparent hugepages

We are installing SAP HANA in a RAID machine. As part of the installation step, it is mentioned that, To disable the usage of transparent hugepages set the kernel settings at runtime with echo ...
2
votes
1answer
334 views

Kernel headers for VMware tools

I tried to compile VMware tools on my server. I compiled the kernel myself, I didn't use RPM. As VMware tools needs the kernel header files, I executed the following command in my kernel folder ...
0
votes
3answers
50 views

Linux Distro name API to get name of linux distro in a driver code?

I am writing a common code in a driver to get the distros name and host name. host name i am taking from struct utsname{nodename[]}, but how do I get the distro name?
55
votes
5answers
27k views

What are high memory and low memory on Linux?

I'm interested in the difference between Highmem and Lowmem: Why is there such a differentiation? What do we gain by doing so? What features does each have?
0
votes
3answers
1k views

Who wrote the “Linux kernel” (Linus Torvalds and his team)?

Who are the authors of the pure Linux kernel from scratch, which was integrated with GNU tools and formed the full GNU/Linux Operating system in the 1990s? I have read some wiki articles but I haven't ...
1
vote
2answers
50 views

Which function in Linux kernel do the powering off action?

I am not asking how to shut down. I am asking how to cut of the power. What is the function in Linux kernel code do the action of cutting of the power? And please explain the code.