[Letux-kernel] OMAP5: Debugging kernel not starting...

Tony Lindgren tony at atomide.com
Mon Sep 10 19:09:15 CEST 2018


* H. Nikolaus Schaller <hns at goldelico.com> [180909 08:46]:
> So what is the canonical way to debug such issues
> with modern kernels? Is it possible to get something
> like printascii()? Or make the kernel log go to a
> fixed address? Or should I hack printk() to write
> a copy to a private buffer at a static address?

First try adding debug earlycon to your kernel command
line. This assumes you have stdout-path in the dts file,
see patch "ARM: dts: Add chosen for earlycon UART" I sent
for pyra last year at some point.

If that does not get you output early enough, there's
the DEBUG_LL option but that's rarely needed nowadays.

And then there's the pstore console support which is
really nice as you have the buffer available after
a warm reset on watchdog reboot etc. But sounds like
that may not help here if you're having trouble with
reboot :)

Regards,

Tony


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