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

learn more… | top users | synonyms

2
votes
1answer
173 views

Choose kernel for specific hardware

I have old system with an AMD Athlon 1,2 GHz processor and [SiS] 65x/M650/740 graphics (output from lspci). Recently I discovered on a german ubuntu page that since version 10.10 some older ...
1
vote
1answer
2k views

Is Native Language Support (NLS) kernel support still necessary?

Does ext4 / cifs system need kernel NLS support ? I'm not sure if it's being handled by user-space program (decoding / encoding) ?
9
votes
2answers
6k views

How to know if a network interface is tap, tun, bridge or physical?

As far as i know, there are 4 main types of network interfaces in linux: tun, tap, bridge and physical. When i'm doing sys admin on machines running KVM, i usually come accross tap, bridge and ...
1
vote
1answer
390 views

Edit the .config file when en/disabling a particular option like CONFIG_CPU_FREQ?

From here: http://www.xenomai.org/index.php/FAQs#Which_kernel_settings_should_be_avoided.3F Which kernel settings should be avoided? Note that Xenomai will warn you about known invalid ...
6
votes
1answer
3k views

WARNING: modpost: Found 10 section mismatch(es)

Is this error message something that I should be worried about? linux-y3pi:/usr/src/linux-2.6.38.8 # make modules scripts/kconfig/conf --silentoldconfig Kconfig CHK include/linux/version.h ...
4
votes
1answer
2k views

How to know whether the Linux driver for the real-time network device was built into the kernel?

From here: http://www.xenomai.org/index.php/RTnet:Installation_%26_Testing#Debugging_RTnet The Linux driver for the real-time network device was built into the kernel and blocks the hardware. ...
1
vote
1answer
326 views

install 2.6.32.59 on squeeze

I'm suffering from a kernel bug in a production environment. The problem isn't causing a complete outage, but it's degrading service. These are soft lockups. I'd like to try a newer kernel, ...
3
votes
1answer
853 views

Is it necessary to enable CONFIG_USB_OHCI_HCD , when there's only USB 2.0 ports

Is it necessary to enable CONFIG_USB_OHCI_HCD on a system that has USB 2.0 port only ? I'm not sure those devices present , e.g bluetooth , camera use that driver ? Bus 001 Device 001: ID 1d6b:0002 ...
1
vote
1answer
422 views

Where is CONFIG_APM in kernel - 2.6.38.8

From here: http://www.xenomai.org/documentation/xenomai-2.6/TROUBLESHOOTING Q: Which CONFIG_* items are latency killers, and should be avoided ? ... APM: The APM model assigns power management ...
1
vote
1answer
118 views

ACPI (Advanced Configuration And Power Configuration) not present on 2.6.38.8?

I need to disable some parts in ACPI, but it is simply not present in kernel 2.6.38.8 (downloaded as a tar from net)? I can see the option in kernel 2.6.34-12 (default on OpenSuse 11.3), but not in ...
0
votes
2answers
967 views

buildroot/busybox: launch bootchartd on startup

I built a custom linux image using buildroot and busybox. To speed up the boot process I'd like to use bootchartd (built-in version of busybox) to profile the process. However bootchartd is not ...
1
vote
1answer
257 views

how to enable sound support in linux kernel without recompile?

I have recently compiled linux kernel 3.2. But at time of compiling in make menuconfig, I had disabled sound support. Now, I want to enable it without recompile it. I don't want to use stock kernel ...
3
votes
3answers
661 views

Why does Linux on sparc64 architecture use 32-bit pointers in user-space and 64-bit pointers in kernel-space?

What are the advantages of deviating from the norm; that is 64-bit pointers in both user and kernel space for a 64-bit architecture? Reference: http://lwn.net/images/pdf/LDD3/ch11.pdf (Page 2)
2
votes
0answers
975 views

Qemu doesn't boot kernel after “Uncompressing Linux… done, booting the kernel. ”

I've compiled qemu for s5pc110 (it's from http://gitorious.org/samsung-linux-platform/qemu, somebody had added support for s5pc110), version 0.12. But when I load the kernel: qemu-system-arm -M ...
98
votes
6answers
153k views

How to reload udev rules without reboot?

How should one reload udev rules, so that newly created one can function? I'm running Arch Linux, and I don't have a udevstart command here. Also checked /etc/rc.d, no udev service there.
16
votes
3answers
5k views

Why don't you need to update drivers? (Or do you?)

In my life I've not once updated drivers on any of my Linux systems, though they have all been desktops. A friend was asking me why one does not need to update Linux drivers and I found myself unable ...
5
votes
1answer
862 views

Needs help on setting up kernel keyboard mapping

I already got the keycode from kernel, but acpi_listen won't recognize it in Arch Linux: # /usr/lib/udev/keymap -i /dev/input/by-path/platform-thinkpad_acpi-event Press ESC to finish, or Control-C if ...
1
vote
2answers
107 views

linux with 3.2.x kernel [closed]

Is there a major Linux distribution that uses 3.2.x kernel?
4
votes
2answers
3k views

vmlinuz and initrd not found after building the kernel?

After configuring and building the kernel using make, why don't I have vmlinuz-<version>-default.img and initrd-<version>.img, but only got a huge vmlinux binary (~150MB)?
2
votes
1answer
581 views

Which edac module should I enable here?

I got a Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz CPU here , not sure which module should be enabled for EDAC: Chipset: Inter Coporation 6 Series/C2000 , driver in use: i801_smbus
3
votes
2answers
3k views

How do I build the iptables kernel module for a loaded kernel?

I've built a kernel with loadable module support for various reasons, one of them the possibility to compile modules and load them without rebooting. This is supposed to be useful when I need a module ...
0
votes
1answer
3k views

Can the Linux kernel be compiled on Mac OS X 10.6.8?

I have a Macbook Pro and I want to build the Linux Kernel. Can I build 3.3.6 on my Mac? How?
3
votes
1answer
2k views

Do I have to list modules in both `/etc/mkinitcpio.conf` and `/etc/rc.conf`?

I've added few modules into mkinitcpio.conf. Are they automatically loaded at kernel boot or with udev if I don't specify them in modules list in rc.conf?
6
votes
2answers
4k views

VirtualBox guest: 16 CPUs detected but only 1 online

I am running VirtualBox (using the Qiime image http://qiime.org/install/virtual_box.html) The physical hardware is a 32 core machine. The virtual machine in VirtualBox has been given 16 cores. When ...
4
votes
1answer
207 views

What does CONFIG_IA32_AOUT do actually?

I'm running a 64bit kernel, already have CONFIG_IA32_EMULATION set, so do I still need CONFIG_IA32_AOUT enabled? From the help in menuconfig, I don't quite get it.
16
votes
3answers
17k views

How can I reserve a block of memory from the Linux kernel?

I have a device that needs a block of memory that is reserved solely for it, without the OS intervening. Is there any way to tell BIOS or the OS that a block of memory is reserved, and it must not ...
24
votes
1answer
3k views

High CPU usage with CFS?

I asked a previous question to try and isolate the source of an increase in CPU usage when moving an application from RHEL 5 to RHEL 6. The analysis that I did for that seems to indicate that it is ...
2
votes
1answer
950 views

Learning how to build my own linux kernel

Reference - http://www.linode.com/wiki/index.php/PV-GRUB#Building_Your_Own_Kernel In order to work with Xen, a number of options that must be selected: CONFIG_PARAVIRT_GUEST=y CONFIG_XEN=y ...
4
votes
3answers
1k views

Does the linux kernel (specifically 2.6 onwards) have any recursive function?

Given the limited fixed size of kernel stack, my guess is that although theoretically we might have a recursive function if its recursion doesn't go too deep, pragmatism would suggest to do away with ...
9
votes
1answer
5k views

Isolating cause of higher CPU usage on RHEL 6 vs RHEL 5

I'm currently looking to move our system from RHEL 5 to RHEL 6, but I've run into a snag with unexpectedly high CPU usage on the RHEL 6 machines. It appears that this may be due at least in some part ...
3
votes
1answer
991 views

Hyperthread and processors Clock, Size, and Capacity

When I enable hyperthreading, CPU size and capacity decrease to about half the non-hyperthreaded value. Since most of my processes use only two cores, should I disable hyperthreading? lshw -C ...
6
votes
3answers
864 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 ...
2
votes
1answer
9k views

/lib/modules/2.6.37.6/build missing in linux puppy? what should I do?

I am new to linux as of yesterday. I'm using linux puppy to try to get the most out of a 10 year old, slow laptop. I installed it fine, no problems there, but as soon as I try to use my usb dongle's ...
7
votes
1answer
626 views

Linux kernel 3.3 power regression

I am using Fedora 16 in my DELL n4110. I recently upgraded the kernel from 3.2 to 3.3. In contradiction to the official claim, my system still drains battery as hell. It only provides 1:30 to 2 hrs of ...
7
votes
2answers
5k views

How can you determine which process scheduler is being used? [duplicate]

I.e. is it the O(1) scheduler, the CFS scheduler, or an older one?
1
vote
2answers
4k views

How to add boot parameters in arch linux

I want to add i915.i915_enable_rc6=1 as a kernel line as described here but I'm unsure where/how exactly.
0
votes
0answers
948 views

adding system calls to kernel without recompiling during implementation

Could anyone tell me if it is possible to add several system calls to the linux kernel (version 2.6.35) and not have to recompile the kernel each time I change one of their implementations (i.e. ...
2
votes
2answers
679 views

Joli OS on ARM devices

I didn't really know where to ask this question, so since Joli OS uses the linux kernel and they don't seem to have a forum here I go. All the official information I could gather says it doesn't work ...
0
votes
0answers
361 views

“TouchPad lost synchronization” errors in dmesg

My openSUSE 11.3 laptop is running slow. dmesg shows the following errors: [ 733.162161] psmouse.c: TouchPad at isa0060/serio4/input0 lost synchronization, throwing 5 bytes away. [ 774.230841] ...
25
votes
4answers
63k views

What's the difference of dmesg output and /var/log/messages?

AFAIK dmesg shows information about kernel and kernel modules, and /var/log/messages also shows information produced by kernel and modules. So what's the difference? Does /var/log/messages ⊂ output ...
2
votes
1answer
458 views

Cannot find config option “CONFIG_CRASH_DUMP” for kdump

I'm studying on kdump which is a linux kernel crash dumping mechansim. According to documentation/kdump/kdump.txt under the kernel source tree, I need to set the kernel config option CONFIG_CRASH_DUMP=...
2
votes
1answer
522 views

360 degree scrolling with Apple Magic Mouse in Linux?

I read that there is out of the box support for the Apple Magic Mouse in recent Linux kernels, but does that include full functionality such as multiple mouse buttons and multitouch?? For me the two ...
2
votes
0answers
321 views

Perform test of aes-ni and aes module in linux kernel

Since both aes-ni and aes module are available in linux kernel , how can I give it a performance test , to decide which one's faster ?
16
votes
4answers
8k views

How can I write to dmesg from command line?

I'd like to write a statement to dmesg. [How] can I do this?
1
vote
1answer
2k views

FreeBSD source and how to build

A few questions about FreeBSD Where/how should I obtain the source code (ex. through terminal, Download off website) How (on ubuntu) should I build it? Before I build it can I customize it (in other ...
1
vote
3answers
279 views

Am I in the right direction for a linux os?

I compiled the linux kernel by downloading it from kernel.org, put it on my desktop, and opened up terminal. I changed to the linux-3.2.13 folder, typed mr proper. Then I use make menuconfig to ...
0
votes
1answer
715 views

init.exe: Caught segmentation fault, core dumped - what is the source of this error

On my embedded device, I have this error showing up after kernel boot: init.exe: Caught segmentation fault, core dumped But I cannot understand why is this happening? If I do battery cut( i.e. ...
2
votes
2answers
1k views

Linux I/O shared memory access

I'm pretty confused on how linux manages I/O shared memory to communicate with devices that use it. If I understood it correctly linux kernel starts mapped at 0x100000 (to avoid the first megabyte ...
3
votes
2answers
2k views

How much RAM can an application allocate on 64-bit x86 Linux systems?

Is it true that a single application can not allocate more than 2 GiBs even if the system has GiBs more free memory when using a 32-bit x86 PAE Linux kernel? Is this limit loosened by 64-bit x86 Linux ...
5
votes
1answer
4k views

What is syscall-template.S?

I've come across a file syscall-template.S more specifically its location is .../sysdeps/unix/syscall-template.S What is this file? Where is it. It is not on my system and I cannot find it in ...