On Sun, Feb 03, 2013 at 12:04:18AM +0100, Simon Baatz wrote:

Hi Jason,

On Thu, Jan 31, 2013 at 05:19:32PM -0700, Jason Gunthorpe wrote:

quoted

On Thu, Jan 31, 2013 at 07:01:09PM -0500, Jason Cooper wrote:

quoted

If you're interested, I still have a few ideas.  One was to wire two USB
serial adapters end to end to create a different console
(console=/dev/ttyUSB0,115200, getty, etc).  Since they would be going
over usb, that's a different clock, so it should work and provide us
with a safety net.

I can't recall, can you still use JTAG once the CPU has hung on a mbus
access?

If so memory dumping the console ring, or cpu registers would get the
answer pretty directly..

My guesses would be the RTC and/or GPIO blocks (the GPIO blinker needs
a clock), based on table 94.

These guesses seem to be dead on:

Moved the RTC module and GPIO modules (keys, leds) out of the way, to
see whether they cause the boot with disabled runit to lock up.

System boots now and SSH login is possible!

# mount -t debugfs debugfs /sys/kernel/debug 
# cat /sys/kernel/debug/clk/tclk/runit/clk_enable_count 
0
# insmod ./gpio_keys.ko 

System locks up.

and, after a reboot:

# insmod ./rtc-mv.ko 

System locks up.

Bingo!

Awesome!  Thanks for running the test Simon!  I see Andrew sent two
patches hopefully fixing these lockups.  I'll wait for your tested-by
and then apply all four to mvebu/fixes:

ARM: kirkwood: of_serial: fix clock gating by removing clock-frequency
ARM: kirkwood: fix to retain gbe MAC addresses for DT kernels
gpio: mvebu: Add clk support to prevent lockup
rtc: rtc-mv: Add support for clk to avoid lockups

I'll push Jason's local-mac-address patch to v3.9.

That should cover everything.

thx,

Jason.