On 03/01/2017 04:25 PM, Nathan Ciobanu wrote:
Debugging a boot issue on a Coreboot Intel machine with both console and earlycon turned on and using a uart serial device to get logs.
Added the following boot parameters:
console=ttyS2,115200,keep
ignore_loglevel
debug verbose
earlycon=uart,mmio32,0xde000000,115200n8
keep_bootcon
This causes the serial driver to crash in early_serial8250_write+0x0/0x1a and by examining with objdump I think the crash actually happens in serial8250_early_in() on the "offset <<= port->regshift;" line.
If I don't use the keep_bootcon parameter then the crash doesn't happen and I can boot just fine and get both earlycon and console output.
Is keep_bootcon not supposed to be used with earlycon uart devices? If so AFAIK this is not documented anywhere.
If keep_bootcon is supposed to be used with earlycon and uart devices then this is a bug.
From older threads on this mailing list I learned that there shouldn't
be a restriction to use keep_bootcon with earlycon the way I described
it before. Still using it causes the crash on multiple IA-based
platforms that use Coreboot instead of BIOS.
I'd like to ping again and ask for help to root cause and hopefully fix
this.
Thanks,
Nathan
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