Messages in this thread | | | From | Bjorn Helgaas <> | Subject | Re: [RFC][PATCH] Way for platforms to alter built-in serial ports | Date | Tue, 2 Nov 2004 09:39:25 -0700 |
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On Monday 01 November 2004 10:15 am, David Woodhouse wrote: > The problem is that 'console=ttySx' doesn't actually do anything unless > port numer 'x' is already registered and working. We should fix that -- > we ought to be able to use 'console=ttySx' on the command line and have > the console get registered with the core printk code later, when some > 8250 sub-driver (8250_platform, 8250_pci, etc.) actually registers the > port which becomes number 'x'.
See serial8250_late_console_init(); does this do what you want?
> That would allow 'early' serial consoles to have none of the horrible > special-cased 'earlyconsole' crap -- we just call register_serial() (or > early_serial_setup() or whatever) as soon as it's actually possible to > poke at the port.
ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.10-rc1/2.6.10-rc1-mm2/broken-out/early-uart-console-support.patch ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.10-rc1/2.6.10-rc1-mm2/broken-out/move-hcdp-pcdp-to-early-uart-console.patch
For platforms that define SERIAL_PORT_DFNS, early boot code could easily recognize "console=ttyS0" and use SERIAL_PORT_DFNS to register "console=uart,io,0x3f8".
If you don't have SERIAL_PORT_DFNS, early boot code doesn't know anything about 'ttySx', so you need some other mechanism to find the device (the user could specify it directly, or firmware could supply it). - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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