Merge remote-tracking branch 'jc_docs/docs-next'

[karo-tx-linux.git] / Documentation / kernel-parameters.txt

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a7fe423326b6a9be8b011725e439e78830b75b3d..ca4f6fbc1206fe71d438d516bb7772b15780c344 100644 (file)
--- 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.
@@ -975,6 +977,10 @@ 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.
+
                cdns,<addr>
                        Start an early, polled-mode console on a cadence serial
                        port at the specified address. The cadence serial port
@@ -2336,11 +2342,12 @@ 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.