Documentation/kernel-parameters.txt and Documentation/x86/x86_64/boot-options.txt contain virtually identical text describing earlyprintk. This consolidates the two copies and updates the documentation a bit. No one ever documented the: earlyprintk=serial,0x1008,115200 syntax, nor mentioned that ARM is now a supported earlyprintk arch. Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> --- linux.git-davehans/Documentation/kernel-parameters.txt | 16 +++++++++-- linux.git-davehans/Documentation/x86/x86_64/boot-options.txt | 14 --------- 2 files changed, 14 insertions(+), 16 deletions(-) diff -puN Documentation/kernel-parameters.txt~early-printk-morettys Documentation/kernel-parameters.txt --- linux.git/Documentation/kernel-parameters.txt~early-printk-morettys 2013-04-10 13:30:37.422949520 -0700 +++ linux.git-davehans/Documentation/kernel-parameters.txt 2013-04-10 13:30:37.428949526 -0700 @@ -757,19 +757,31 @@ bytes respectively. Such letter suffixes (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 -puN Documentation/x86/x86_64/boot-options.txt~early-printk-morettys Documentation/x86/x86_64/boot-options.txt --- linux.git/Documentation/x86/x86_64/boot-options.txt~early-printk-morettys 2013-04-10 13:30:37.424949522 -0700 +++ linux.git-davehans/Documentation/x86/x86_64/boot-options.txt 2013-04-10 13:30:37.428949526 -0700 @@ -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 _ -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
