diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 16 | ||||
| -rw-r--r-- | Documentation/x86/x86_64/boot-options.txt | 14 |
2 files changed, 14 insertions, 16 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4609e81dbc37..b5cfd047becb 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -757,19 +757,31 @@ bytes respectively. Such letter suffixes can also be entirely omitted. (mmio) or 32-bit (mmio32). The options are the same as for ttyS, above. - earlyprintk= [X86,SH,BLACKFIN] + earlyprintk= [X86,SH,BLACKFIN,ARM] earlyprintk=vga earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] + earlyprintk=serial[,0x...[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] + earlyprintk is useful when the kernel crashes before + the normal console is initialized. It is not enabled by + default because it has some cosmetic problems. + Append ",keep" to not disable it when the real console takes over. Only vga or serial or usb debug port at a time. - Currently only ttyS0 and ttyS1 are supported. + Currently only ttyS0 and ttyS1 may be specified by + name. Other I/O ports may be explicitly specified + on some architectures (x86 and arm at least) by + replacing ttySn with an I/O port address, like this: + earlyprintk=serial,0x1008,115200 + You can find the port for a given device in + /proc/tty/driver/serial: + 2: uart:ST16650V2 port:00001008 irq:18 ... Interaction with the standard serial driver is not very good. diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt index e015a83c3996..e9e8ddbbf376 100644 --- a/Documentation/x86/x86_64/boot-options.txt +++ b/Documentation/x86/x86_64/boot-options.txt @@ -91,20 +91,6 @@ APICs apicmaintimer. Useful when your PIT timer is totally broken. -Early Console - - syntax: earlyprintk=vga - earlyprintk=serial[,ttySn[,baudrate]] - - The early console is useful when the kernel crashes before the - normal console is initialized. It is not enabled by - default because it has some cosmetic problems. - Append ,keep to not disable it when the real console takes over. - Only vga or serial at a time, not both. - Currently only ttyS0 and ttyS1 are supported. - Interaction with the standard serial driver is not very good. - The VGA output is eventually overwritten by the real console. - Timing notsc |
