path: root/Documentation/kernel-parameters.txt
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authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-05 15:59:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-05 15:59:24 -0800
commit5ebe0ee802c52cdf0c0eed8f3eccc9a056e412a3 (patch)
tree0eb28b0315a44593404f58b9758d31e0afc41425 /Documentation/kernel-parameters.txt
parent1873499e13648a2dd01a394ed3217c9290921b3d (diff)
parent3ce96239d482a7d2dfdc1f332152c580b219fef1 (diff)
Merge tag 'docs-for-linus' of git://git.lwn.net/linux
Pull documentation update from Jon Corbet: "There is a nice new document from Neil on how pathname lookups work and some new CAN driver documentation. Beyond that, we have kernel-doc fixes, a bit more work to support reproducible builds, and the usual collection of small fixes" * tag 'docs-for-linus' of git://git.lwn.net/linux: (34 commits) Documentation: add new description of path-name lookup. Documentation/vm/slub.txt: document slabinfo-gnuplot.sh Doc: ABI/stable: Fix typo in ABI/stable doc: Clarify that nmi_watchdog param is for hardlockups Typo correction for description in gpio document. DocBook: Fix kernel-doc to be case-insensitive for private: kernel-docs.txt: update kernelnewbies reference Doc:kvm: Fix typo in Doc/virtual/kvm Documentation/Changes: Add bc in "Current Minimal Requirements" section Documentation/email-clients.txt: remove trailing whitespace DocBook: Use a fixed encoding for output MAINTAINERS: The docs tree has moved Docs/kernel-parameters: Add earlycon devicetree usage SubmittingPatches: make Subject examples match the de facto standard Documentation: gpio: mention that <function>-gpio has been deprecated Documentation: cgroups: just fix a few typos Documentation: Update kselftest.txt Documentation: DMA API: Be more explicit that nents is always the same Documentation: Update the default value of crashkernel low zram: update documentation ...
Diffstat (limited to 'Documentation/kernel-parameters.txt')
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6263a2da3e2f..688760f790b1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -790,8 +790,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
is passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
- requires at least 64M+32K low memory. Kernel would
- try to allocate 72M below 4G automatically.
+ requires at least 64M+32K low memory, also enough extra
+ low memory is needed to make sure DMA buffers for 32-bit
+ devices won't run out. Kernel would try to allocate at
+ at least 256M below 4G automatically.
This one let user to specify own low range under 4G
for second kernel instead.
0: to disable low allocation.
@@ -972,6 +974,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
earlycon= [KNL] Output early console device and options.
+ When used with no options, the early console is
+ determined by the stdout-path property in device
+ tree's chosen node.
Start an early, polled-mode console on a cadence serial
port at the specified address. The cadence serial port
@@ -2340,11 +2346,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
Format: [panic,][nopanic,][num]
Valid num: 0 or 1
- 0 - turn nmi_watchdog off
- 1 - turn nmi_watchdog on
+ 0 - turn hardlockup detector in nmi_watchdog off
+ 1 - turn hardlockup detector in nmi_watchdog on
When panic is specified, panic when an NMI watchdog
timeout occurs (or 'nopanic' to override the opposite
- default).
+ default). To disable both hard and soft lockup detectors,
+ please see 'nowatchdog'.
This is useful when you use a panic=... timeout and
need the box quickly up again.

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