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

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cc1: warnings being treated as errors when compile FreeBSD 8.2 Release

I am trying to compile FreeBsd 8.2 RELEASE kernel # uname -a FreeBSD 8.2-RELEASE FreeBSD 8.2-RELEASE #2: Sun May 18 00:07:10 PDT 2014 Build the kernel # pwd /usr/src # make buildkernel ... it ...
24
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1answer
12k views

Kernel inotify watch limit reached

I'm currently facing a problem on a linux box where as root I have commands returning error because inotify watch limit has been reached. # tail -f /var/log/messages [...] tail: cannot watch ...
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1answer
34 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 ...
2
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1answer
381 views

Wireless constantly reconnecting on Ideapad running Arch

I just bought a new laptop, a Lenovo IdeaPad U330 touch, and after some struggle (with the Secure Boot stupidity) I have managed to install Arch Linux. I have configured my system, installed all the ...
4
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1answer
280 views

How to enable VESA framebuffer as default in NetBSD 6.1

When booting NetBSD, the old Tecra 720CDT that I have, works quite nicely in 1024x768x15 mode with vesa fb. I always have to activate VESA when booting the system: > vesa on > vesa 0x116 > ...
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45 views

CPU load and power management (frequency)

question background In my understanding the load value (shown e.g. by top) allows (together with the knowledge how many CPU cores the system has) a very quick assessment which share of the ...
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41 views

loading ath9k_htc kernel driver fails

could someone please point me in the right direction to get my external wireless stick (TL-WN722N) working on my Xperia Neo (haida) smartphone? So far I've done the following: I downloaded ...
18
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3answers
188 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 ...
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34 views

Debian Squeeze: TCP/ICMP stops working suddenly (R8169 Driver)

we suddenly see our NETWORKING stops (TCP/UDP/ICMP) in our client system. tcp: We tried reaching our server every 5 seconds.But , there was no connection establishment TCPDUMP REF: ...
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3answers
4k views

Why is Linux NFS server implemented in the kernel as opposed to userspace?

I was just wondering why the Linux NFS server is implemented in the kernel as opposed to a userspace application? I know a userspace NFS daemon exists, but it's not the standard method for providing ...
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2answers
1k 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 ...
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71 views

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 ...
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21 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.
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0answers
29 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 ...
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2answers
45 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 ...
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1answer
1k 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' ...
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27 views

real time kernel / low latency comes from the vanilla source

Does the vanilla source provide real time / low latency functionality ?
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26 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 ...
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1answer
20 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 ...
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1answer
64 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 ...
0
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1answer
129 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
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1answer
903 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 ...
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1answer
30 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 ...
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50 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 ...
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38 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. ...
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1answer
463 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 ...
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306 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 ...
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2answers
843 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 ...
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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 ...
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1answer
145 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 ...
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1answer
142 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 ...
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1answer
46 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 ...
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466 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 ...
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61 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) ). ...
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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 ...
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1answer
176 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 ...
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1answer
132 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 ...
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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 ...
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26 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 ...
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3answers
53 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?
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5answers
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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?
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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 ...
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2answers
52 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.
1
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1answer
23 views

What directory houses the scripts that get executed with new kernel installations?

This one is pretty much a straightfoward question/answer I just can't locate the information. I'm trying to automate the re-installation of VMWare tools based off when a new kernel is installed. I ...
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0answers
29 views

RHEL 6.5 erroneously marking Fusion-io RAID1 card as failed

I am getting the following error every hour for a Fusion-io ioscale2 RAID1 (mirror) configuration. However, the logical volume is mounted and accessible. I do not see similar error in the ...
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1answer
55 views

How can I boot into Ubuntu with a linux kernel with an earlier version?

Part of the output of ls -ld /usr/src/linux-headers* on ubuntu 12.04 is: drwxr-xr-x 24 root root 4096 Jun 4 2013 /usr/src/linux-headers-3.2.0-45 drwxr-xr-x 7 root root 4096 Jun 4 2013 ...
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1answer
120 views

yum update returns kernel error

I want to install virtualbox in fedora20. I have followed the instruction here: http://www.if-not-true-then-false.com/2010/install-virtualbox-with-yum-on-fedora-centos-red-hat-rhel/ but when I ...
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0answers
33 views

How/where are linux device capabilities / bitfields set?

I have a device that has this output in /proc/bus/input/devices: I: Bus=0003 Vendor=05b8 Product=3280 Version=0111 N: Name="PixArt USB Optical Mouse" P: Phys=usb-0000:00:1a.0-1.1/input0 S: ...
13
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3answers
237 views

How to force Linux kernel to “freeze” (or nearly freeze) for a few hundred milliseconds

We are running a real-time process on a non real-time kernel (CentOS 6), and this is probably not going to change. We have a streaming video application that requires about 500 MB/s of PCIe traffic ...
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How do I set kernel-ml default in CentOS?

I have installed kernel-ml package from http://elrepo.org/tiki/kernel-ml Now I have both the original CentOS kernel and kernel-ml. How do I set kernel-ml as default on boot? Thank you!