Remote Access to H/W
loic.minier at linaro.org
Fri Feb 25 13:13:00 UTC 2011
On Fri, Feb 25, 2011, Andy Green wrote:
> You can ssh into a second "buddy" box who has a serial connection to
> the target box's serial port (in the 1&1 case they set grub even to
> issue serial menus). The buddy box also controls the target via a
> smart power switch.
Yup; I'm familiar with this idea (well, except my hosting provider
doesn't have a serial line, they just start an Ubuntu live CD with VNC
and SSH) and we do have remote controlled power, but...
> When you cycle the target power using a web interface to the buddy
> box, you can also select to force a canned boot path sent over
> bootp, so even a trashed box with no bootloader can be recovered.
not all boards boot when power-cycled (!) and you can't test the
default bootloader with this approach (e.g. if your card only boots
from SD and you want to test u-boot-linaro on SD, you might not be able
to recover from a broken bootloader), but for the kernel that would be
fine. I think almost all our current boards boot when power-cycled
> It's not far away from being workable on embedded boards, maybe by
> having an adapter card that sites two SD cards in one slot, you can
> enable the normal one or a backup read-only one based on a line
> controlled by its buddy box.
adapter card > interesting idea! Does this require us to build custom
hardware, or does this exist on the shelves already?
On Fri, Feb 25, 2011, Dave Martin wrote:
> On vexpress for example, we have a known-good U-Boot in flash which
> can be used to recover the board if needed.
That's good if you have flash, yup (unless you're testing the
bootloader in flash, but we currently never want to do this).
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