On 01/05/12 23:19, Peter Naulls wrote:
On 01/05/2012 09:43 AM, Florian Fainelli wrote:
Hello,
You should enable kernel debugging in your kexec'd kernel and see
whether the
serial port is being left with IRQs disabled from the original kernel.
I turned on kernel debug, but I'm unsure what exactly I'm looking at.
Look for unhandled IRQs which should lead to the message "irq <N> nobody
cared" if this is the cause of the problem.
It may be that the serial port is flooding the kernel with IRQs not
handled
which in turn causes a reboot.
Otherwise, just dump the serial port register contents before leaving
the
original kernel, and at driver initialization of the kexec'd kernel
to see if
there are any differences.
Sure, but which registers am I looking at - 8250, or something arxx
specific?
8250 registers, which are memory-mapped into the CPU address space.
I went as far as to set:
CONFIG_SERIAL_8250_NR_UARTS=0
CONFIG_SERIAL_8250_RUNTIME_UARTS=0
But this might not be enough by itself. It still reboots at that same
point. I also tried disabling early printk.
Then this might be an entirely different issue. Try to run the kexec'd
kernel uncached and see if that helps (there is a MIPS-specific Kconfig
option to do that).
--
Florian
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