Re: [Xen-ia64-devel] Serial woes with kexec on an HP RX2620

[Horms <horms@xxxxxxxxxxxx>]

On Wed, May 23, 2007 at 01:36:45PM +0900, Akio Takebe wrote:
> Hi, Horms
> 
> After kexec, what kernel do you use?
> Xen or linux kernel?
> 
> I think you don't call iosapic_register_intr(),
> arguments of iosapic_register_intr() are wrong.
> Can you check that efi.hcdp is passed to second kernel properly?
> 
> FYI
> In the case of xen, HP machine call the following functions. 
> efi_setup_pcdp_console()
>     setup_serial_console()
>         setup_pcdp_irq()
>             pcdp_hp_irq_fixup()
> 
> And iosapic_register_intr() is called in start_kernel().

I took a look over those code paths and couldn't find
anything particularly interesting.

The fixup
code in pcdp_hp_irq_fixup() is not invoked, as the
rx2620 that I have seems to have pcdp->rev = 3.
The values sourced from inside the pcdp seem to be
the same as what the fixup would have set, so no drama there.

I did find one thing which is interesting, which is that if
I boot into the first kernel with xencons_poll, and the second
kernel without it, then the console in both kernels works.
I wonder if perhaps the first kernel needs to unhook something
irq related.

For completeness I tested all the combinations of booting with
and without xencons_poll

First Kernel     Second Kernel
     -                -          No input on serial console
     -           xencons_poll    Success
xencons_poll          -          Success
xencons_poll     xencons_poll    Success

-- 
Horms
  H: http://www.vergenet.net/~horms/
  W: http://www.valinux.co.jp/en/


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