Messages in this thread | | | Subject | Re: [RFC][PATCH] Way for platforms to alter built-in serial ports | From | David Woodhouse <> | Date | Mon, 01 Nov 2004 17:15:48 +0000 |
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On Wed, 2004-10-06 at 08:29 +0100, Russell King wrote: > The only reason it exists in its current form is because Alan says > we can't get rid of the serial port initialisation due to the x86 > requirement for serial console to be initialised reasonably early. > > Unfortunately the early console stuff (afaik) never made it in to > the kernel, so we've had to keep this hanging around. > > Maybe once this problem is solved we can consider dwmw2's suggestion.
Serial console working really early isn't just a requirement for x86. It's useful elsewhere too.
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'.
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.
It also fixes the case of serial console on a PCI device.
-- dwmw2
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