Merge tag 'docs-4.5' of git://git.lwn.net/linux
[cascardo/linux.git] / Documentation / kernel-parameters.txt
index 5e80a9b..3ea869d 100644 (file)
@@ -472,6 +472,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        Change the amount of debugging information output
                        when initialising the APIC and IO-APIC components.
 
+       apic_extnmi=    [APIC,X86] External NMI delivery setting
+                       Format: { bsp (default) | all | none }
+                       bsp:  External NMI is delivered only to CPU 0
+                       all:  External NMIs are broadcast to all CPUs as a
+                             backup of CPU 0
+                       none: External NMI is masked for all CPUs. This is
+                             useful so that a dump capture kernel won't be
+                             shot down by NMI
+
        autoconf=       [IPV6]
                        See Documentation/networking/ipv6.txt.
 
@@ -599,6 +608,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        cut the overhead, others just disable the usage. So
                        only cgroup_disable=memory is actually worthy}
 
+       cgroup.memory=  [KNL] Pass options to the cgroup memory controller.
+                       Format: <string>
+                       nosocket -- Disable socket memory accounting.
+
        checkreqprot    [SELINUX] Set initial checkreqprot flag value.
                        Format: { "0" | "1" }
                        See security/selinux/Kconfig help text.
@@ -721,16 +734,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
                uart[8250],io,<addr>[,options]
                uart[8250],mmio,<addr>[,options]
+               uart[8250],mmio16,<addr>[,options]
                uart[8250],mmio32,<addr>[,options]
                uart[8250],0x<addr>[,options]
                        Start an early, polled-mode console on the 8250/16550
                        UART at the specified I/O port or MMIO address,
                        switching to the matching ttyS device later.
                        MMIO inter-register address stride is either 8-bit
-                       (mmio) or 32-bit (mmio32).
-                       If none of [io|mmio|mmio32], <addr> is assumed to be
-                       equivalent to 'mmio'. 'options' are specified in the
-                       same format described for ttyS above; if unspecified,
+                       (mmio), 16-bit (mmio16), or 32-bit (mmio32).
+                       If none of [io|mmio|mmio16|mmio32], <addr> is assumed
+                       to be equivalent to 'mmio'. 'options' are specified in
+                       the same format described for ttyS above; if unspecified,
                        the h/w is not re-initialized.
 
                hvc<n>  Use the hypervisor console device <n>. This is for
@@ -1002,10 +1016,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        unspecified, the h/w is not initialized.
 
                pl011,<addr>
+               pl011,mmio32,<addr>
                        Start an early, polled-mode console on a pl011 serial
                        port at the specified address. The pl011 serial port
                        must already be setup and configured. Options are not
-                       yet supported.
+                       yet supported.  If 'mmio32' is specified, then only
+                       the driver will use only 32-bit accessors to read/write
+                       the device registers.
 
                msm_serial,<addr>
                        Start an early, polled-mode console on an msm serial
@@ -1583,9 +1600,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                hwp_only
                        Only load intel_pstate on systems which support
                        hardware P state control (HWP) if available.
-               no_acpi
-                       Don't use ACPI processor performance control objects
-                       _PSS and _PPC specified limits.
 
        intremap=       [X86-64, Intel-IOMMU]
                        on      enable Interrupt Remapping (default)
@@ -2578,8 +2592,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        notsc           [BUGS=X86-32] Disable Time Stamp Counter
 
-       nousb           [USB] Disable the USB subsystem
-
        nowatchdog      [KNL] Disable both lockup detectors, i.e.
                         soft-lockup and NMI watchdog (hard-lockup).
 
@@ -2987,6 +2999,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        may be specified.
                        Format: <port>,<port>....
 
+       ppc_strict_facility_enable
+                       [PPC] This option catches any kernel floating point,
+                       Altivec, VSX and SPE outside of regions specifically
+                       allowed (eg kernel_enable_fpu()/kernel_disable_fpu()).
+                       There is some performance impact when enabling this.
+
        print-fatal-signals=
                        [KNL] debug: print fatal signals
 
@@ -3302,18 +3320,35 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        rcutorture.verbose= [KNL]
                        Enable additional printk() statements.
 
+       rcupdate.rcu_cpu_stall_suppress= [KNL]
+                       Suppress RCU CPU stall warning messages.
+
+       rcupdate.rcu_cpu_stall_timeout= [KNL]
+                       Set timeout for RCU CPU stall warning messages.
+
        rcupdate.rcu_expedited= [KNL]
                        Use expedited grace-period primitives, for
                        example, synchronize_rcu_expedited() instead
                        of synchronize_rcu().  This reduces latency,
                        but can increase CPU utilization, degrade
                        real-time latency, and degrade energy efficiency.
-
-       rcupdate.rcu_cpu_stall_suppress= [KNL]
-                       Suppress RCU CPU stall warning messages.
-
-       rcupdate.rcu_cpu_stall_timeout= [KNL]
-                       Set timeout for RCU CPU stall warning messages.
+                       No effect on CONFIG_TINY_RCU kernels.
+
+       rcupdate.rcu_normal= [KNL]
+                       Use only normal grace-period primitives,
+                       for example, synchronize_rcu() instead of
+                       synchronize_rcu_expedited().  This improves
+                       real-time latency, CPU utilization, and
+                       energy efficiency, but can expose users to
+                       increased grace-period latency.  This parameter
+                       overrides rcupdate.rcu_expedited.  No effect on
+                       CONFIG_TINY_RCU kernels.
+
+       rcupdate.rcu_normal_after_boot= [KNL]
+                       Once boot has completed (that is, after
+                       rcu_end_inkernel_boot() has been invoked), use
+                       only normal grace-period primitives.  No effect
+                       on CONFIG_TINY_RCU kernels.
 
        rcupdate.rcu_task_stall_timeout= [KNL]
                        Set timeout in jiffies for RCU task stall warning
@@ -3880,6 +3915,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        usbcore.usbfs_snoop=
                        [USB] Set to log all usbfs traffic (default 0 = off).
 
+       usbcore.usbfs_snoop_max=
+                       [USB] Maximum number of bytes to snoop in each URB
+                       (default = 65536).
+
        usbcore.blinkenlights=
                        [USB] Set to cycle leds on hubs (default 0 = off).
 
@@ -3900,6 +3939,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         USB_REQ_GET_DESCRIPTOR request in milliseconds
                        (default 5000 = 5.0 seconds).
 
+       usbcore.nousb   [USB] Disable the USB subsystem
+
        usbhid.mousepoll=
                        [USBHID] The interval which mice are to be polled at.
 
@@ -4120,6 +4161,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        or other driver-specific files in the
                        Documentation/watchdog/ directory.
 
+       workqueue.watchdog_thresh=
+                       If CONFIG_WQ_WATCHDOG is configured, workqueue can
+                       warn stall conditions and dump internal state to
+                       help debugging.  0 disables workqueue stall
+                       detection; otherwise, it's the stall threshold
+                       duration in seconds.  The default value is 30 and
+                       it can be updated at runtime by writing to the
+                       corresponding sysfs file.
+
        workqueue.disable_numa
                        By default, all work items queued to unbound
                        workqueues are affine to the NUMA nodes they're