Remote Access to H/W
gadiyar at ti.com
Fri Feb 25 13:21:12 UTC 2011
Dave Martin wrote:
> On Fri, Feb 25, 2011 at 10:58 AM, Loďc Minier
> <loic.minier at linaro.org> wrote:
> > On Thu, Feb 24, 2011, Mounir Bsaibes wrote:
> >> We have a need for a Panda and a Beagle to compare & fix performance.
> >> As I recall from last meeting, the Panda's USB I/O has 2x performance
> >> degradation from Beagle.
> >> Per or Mian may have more details on that.
> > Ok; interesting!
> > My initial fear was that the kernel testing might trigger unbootable
> > boards and that it would be tricky to work with unstable kernels
> > remotely; for USB performance testing, I can see that we could set it
> > up for remote testing, but we need to have something plugged to USB
> > be careful to use the same hardware on both boards so that it
> > usefully.
> If we never upgrade the bootloader, and make sure that the known-good
> bootscripts/images are never modified/removed, then we should
> generally be able to avoid bricking.
> On vexpress for example, we have a known-good U-Boot in flash which
> can be used to recover the board if needed.
> Where random hardware has to be plugged in, that could be a bit harder
> to arrange...
I work remotely with my Pandaboard - I have the UART plugged into
a desktop and a USB relay board for the power supply. I have
a screen session with picocom running on the desktop all the time.
I keep known-working loaders on the SD card with a "uImage-flasher"
image alongside. (Essentially a kernel with drivers enabled for the EHCI
controller and the USB-LAN chip + initramfs + tiny scripts that pick
up a kernel image from a hardcoded location using tftp and replace
the one currently on the SD card.
To get into the flasher image, I just halt manually in u-boot and
load uimage-flasher. Else, u-boot is configured to pick up 'uImage'
- Can't work remotely if you're working on x-loader code (flashing
a wrong image MLO/u-boot could mean a physical visit to the board)
--- Okay for u-boot if you want to load u-boot from within a known-
- Someone 'borrows' the board without asking.
--- I've had folks walk in, see the board apparently unused, and
borrow it for a - leaving me wondering why the board stopped
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