Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git...

[cascardo/linux.git] / Documentation / kernel-parameters.txt

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 25037de..705fb91 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -460,6 +460,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        driver will print ACPI tables for AMD IOMMU during
                        IOMMU initialization.
 
                        driver will print ACPI tables for AMD IOMMU during
                        IOMMU initialization.
 

+       amd_iommu_intr= [HW,X86-64]
+                       Specifies one of the following AMD IOMMU interrupt
+                       remapping modes:
+                       legacy     - Use legacy interrupt remapping mode.
+                       vapic      - Use virtual APIC mode, which allows IOMMU
+                                    to inject interrupts directly into guest.
+                                    This mode requires kvm-amd.avic=1.
+                                    (Default when IOMMU HW support is present.)
+

        amijoy.map=     [HW,JOY] Amiga joystick support
                        Map of devices attached to JOY0DAT and JOY1DAT
                        Format: <a>,<b>
        amijoy.map=     [HW,JOY] Amiga joystick support
                        Map of devices attached to JOY0DAT and JOY1DAT
                        Format: <a>,<b>


@@ -1054,11 +1063,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        determined by the stdout-path property in device
                        tree's chosen node.
 
                        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
-                       must already be setup and configured. Options are not
-                       yet supported.
+               cdns,<addr>[,options]
+                       Start an early, polled-mode console on a Cadence
+                       (xuartps) serial port at the specified address. Only
+                       supported option is baud rate. If baud rate is not
+                       specified, the serial port must already be setup and
+                       configured.

 
                uart[8250],io,<addr>[,options]
                uart[8250],mmio,<addr>[,options]
 
                uart[8250],io,<addr>[,options]
                uart[8250],mmio,<addr>[,options]


@@ -1373,6 +1383,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
                        Default: 1024
 
                        Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
                        Default: 1024
 

+       gpio-mockup.gpio_mockup_ranges
+                       [HW] Sets the ranges of gpiochip of for this device.
+                       Format: <start1>,<end1>,<start2>,<end2>...
+

        hardlockup_all_cpu_backtrace=
                        [KNL] Should the hard-lockup detector generate
                        backtraces on all cpus.
        hardlockup_all_cpu_backtrace=
                        [KNL] Should the hard-lockup detector generate
                        backtraces on all cpus.


@@ -1652,6 +1666,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        initrd=         [BOOT] Specify the location of the initial ramdisk
 
 
        initrd=         [BOOT] Specify the location of the initial ramdisk
 

+       init_pkru=      [x86] Specify the default memory protection keys rights
+                       register contents for all processes.  0x55555554 by
+                       default (disallow access to all but pkey 0).  Can
+                       override in debugfs after boot.
+

        inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
                        Format: <irq>
 
        inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
                        Format: <irq>
 


@@ -1697,7 +1716,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        intel_idle.max_cstate=  [KNL,HW,ACPI,X86]
                        0       disables intel_idle and fall back on acpi_idle.
 
        intel_idle.max_cstate=  [KNL,HW,ACPI,X86]
                        0       disables intel_idle and fall back on acpi_idle.

-                       1 to 6  specify maximum depth of C-state.
+                       1 to 9  specify maximum depth of C-state.

 
        intel_pstate=  [X86]
                       disable
 
        intel_pstate=  [X86]
                       disable


@@ -2170,10 +2189,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        than or equal to this physical address is ignored.
 
        maxcpus=        [SMP] Maximum number of processors that an SMP kernel
                        than or equal to this physical address is ignored.
 
        maxcpus=        [SMP] Maximum number of processors that an SMP kernel

-                       should make use of.  maxcpus=n : n >= 0 limits the
-                       kernel to using 'n' processors.  n=0 is a special case,
-                       it is equivalent to "nosmp", which also disables
-                       the IO APIC.
+                       will bring up during bootup.  maxcpus=n : n >= 0 limits
+                       the kernel to bring up 'n' processors. Surely after
+                       bootup you can bring up the other plugged cpu by executing
+                       "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
+                       only takes effect during system bootup.
+                       While n=0 is a special case, it is equivalent to "nosmp",
+                       which also disables the IO APIC.

 
        max_loop=       [LOOP] The number of loop block devices that get
        (loop.max_loop) unconditionally pre-created at init time. The default
 
        max_loop=       [LOOP] The number of loop block devices that get
        (loop.max_loop) unconditionally pre-created at init time. The default


@@ -2580,8 +2602,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        nodelayacct     [KNL] Disable per-task delay accounting
 
 
        nodelayacct     [KNL] Disable per-task delay accounting
 

-       nodisconnect    [HW,SCSI,M68K] Disables SCSI disconnects.
-

        nodsp           [SH] Disable hardware DSP at boot time.
 
        noefi           Disable EFI runtime services support.
        nodsp           [SH] Disable hardware DSP at boot time.
 
        noefi           Disable EFI runtime services support.


@@ -2782,9 +2802,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        nr_cpus=        [SMP] Maximum number of processors that an SMP kernel
                        could support.  nr_cpus=n : n >= 1 limits the kernel to
 
        nr_cpus=        [SMP] Maximum number of processors that an SMP kernel
                        could support.  nr_cpus=n : n >= 1 limits the kernel to

-                       supporting 'n' processors. Later in runtime you can not
-                       use hotplug cpu feature to put more cpu back to online.
-                       just like you compile the kernel NR_CPUS=n
+                       support 'n' processors. It could be larger than the
+                       number of already plugged CPU during bootup, later in
+                       runtime you can physically add extra cpu until it reaches
+                       n. So during boot up some boot time memory for per-cpu
+                       variables need be pre-allocated for later physical cpu
+                       hot plugging.

 
        nr_uarts=       [SERIAL] maximum number of UARTs to be registered.
 
 
        nr_uarts=       [SERIAL] maximum number of UARTs to be registered.
 


@@ -4247,6 +4270,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                                u = IGNORE_UAS (don't bind to the uas driver);
                                w = NO_WP_DETECT (don't test whether the
                                        medium is write-protected).
                                u = IGNORE_UAS (don't bind to the uas driver);
                                w = NO_WP_DETECT (don't test whether the
                                        medium is write-protected).

+                               y = ALWAYS_SYNC (issue a SYNCHRONIZE_CACHE
+                                       even if the device claims no cache)

                        Example: quirks=0419:aaf5:rl,0421:0433:rc
 
        user_debug=     [KNL,ARM]
                        Example: quirks=0419:aaf5:rl,0421:0433:rc
 
        user_debug=     [KNL,ARM]