Questions tagged [kernel-parameters]
121 questions
10
votes
1 answer
Cannot compile kernel: error, kernel does not support PIC mode
I have troubles recompiling my Kernel. Downloading the source package, decompress it and running
fakeroot make-kpkg kernel_image
leads me to the error
[...]
CHK include/generated/utsrelease.h
UPD …
user123456
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9
votes
1 answer
Linux 3.x fails assigning PCI BAR memory
I got an IBM x3850 type 8864 machine, I can successfully boot using a 2.6.32 kernel but when I try to use a 3.10 kernel or newer the kernel fails to initialize all PCI slots (I can fix this (manually), see below):
pci 0000:19:00.0: BAR 14: can't…
Jan
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8
votes
3 answers
Select graphics card for console output
I have an HP DL380G9 server with two discreet nvidia graphics card installed running RHEL 6 with Kernel 2.6.32-573. Both cards have the same chipset (NV117) but different models. K620 (Slot 5 address 88:00.0), K2200 (Slot 4 address 84:00.0). The…
pacmanwa
- 359
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7
votes
2 answers
Difference between net.ipv4.conf.all.forwarding and net.ipv4.ip_forward
According to https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
conf/all/* is special, changes the settings for all interfaces
forwarding - BOOLEAN
Enable IP forwarding on this interface. This controls whether packets
…
Ahmed Gasanov
- 71
- 2
7
votes
1 answer
How to set sysctl using kernel command line parameter?
Is it possible to set Linux kernel sysctl settings (those usually set in /etc/sysctl.d) using kernel command line (those visible in /proc/cmdline)?
(Using grub config file /etc/default/grub variable GRUB_CMDLINE_LINUX="...".)
adrelanos
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7
votes
1 answer
Can no_console_suspend be set in runtime?
Is it possible to change this value in runtime without rebooting? I don't always have this problem, when I suspend right now I'm getting a failure and
Suspending console(s) (use no_console_suspend to debug)
I would like to debug now, without…
Evan Carroll
- 28,578
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7
votes
2 answers
LUKS discard/TRIM: conflicting kernel command line options
I'm confused between the various ways that LUKS/dmcrypt/cryptsetup discard /TRIM operations can be enabled via the Linux kernel command line.
The dracut manpage:
rd.luks.allow-discards
Allow using of discards (TRIM) requests on all LUKS…
Tom Hale
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6
votes
1 answer
Difference between modprobe and sysctl -w in terms of setting system parameters?
We know that sysctl command can change kernel parameters with :
# sysctl -w kernel.domainname="example.com"
or by directly editing the file in /proc/sys directory. And for persistent changes, the parameters must be written to…
Somenath Sinha
- 403
- 5
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6
votes
1 answer
LUKS password not being requested by dmcrypt / encrypt hook at boot
At boot I see:
:: running hook [encrypt]
A password is required to access the volume:
Command requires device and mapped name as arguments
Command requires device and mapped name as arguments
Command requires device and mapped name as…
Tom Hale
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5
votes
4 answers
Finetuning kernel for high swap environment
I own an 8GB RAM Dell XPS13 9343; the amount of RAM is the biggest pain of this computer, it's soldered on mainboard. Despite the CPU supporting more RAM, even resoldering bigger ones with firmware modification is not an option due to the mainboard…
nusch
- 61
- 2
5
votes
1 answer
lsmod 'used by' shows -1 while CONFIG_MODULE_UNLOAD=y
In this post there is some explanation about why does lsmod show -2 in 'used by' column. The idea is that the kernel config option CONFIG_MODULE_UNLOAD was not set.
But what if lsmod shows -1 only for one specific module while CONFIG_MODULE_UNLOAD…
z0lupka
- 275
- 2
- 11
5
votes
2 answers
Kernel parameters are not changed permanently for RHEL7
Trying to permanently change some vm kernel parameters, I created /etc/sysctl.d/01-custom.conf config file as it described in Red Hat knowledgebase article. Here is its content:
# cat…
sys463
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5
votes
0 answers
Grub.conf vs sysctl.conf
Both files are being used to pass parameters to the kernel. so what exacly is the difference between the two? What is the purpose of each file?
Liron Cohen
- 235
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5
votes
2 answers
What are methods for recovering a Linux Kernel config?
I'm currently trying to rebuild the kernel for a proprietary device. In order to do this I will need to produce a kernel config for the device. While I could likely do this through trial and error, it would be better to see if I can extract the…
Brian Redbeard
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5
votes
1 answer
Kernel parameters "console" and "earlycon" refer to old hardware?
I first found this by investigating parameters for earlycon but found that the options for console look almost identical. Both are present below and were taken from this source:
From documentation for console we have:
console= [KNL] Output…
sherrellbc
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