linux-3.6.7-rt18 smoke test on ARM

linux-3.6.7-rt18 smoke test on ARM

[Frank Rowand]

3.6.7-rt18 builds and boots on some ARM boards (PandaBoard, Realview) for:

  - SMP, PREEMPT_RT_FULL
  - SMP, PREEMPT_NONE
  - UP, PREEMPT_RT_FULL
  - UP, PREEMPT_NONE


A patch is required to resolve a BUG_ON() from preempt_schedule_irq().
The patch is available at https://lkml.org/lkml/2012/11/29/432

The PandaBoard frequently fails to boot with an eth0 error.  I have
only seen this for SMP, PREEMPT_NONE.  This same error also occurs
in 3.6.7 without the RT_PREEMPT patches applied, so this does not
appear to be an RT_PREEMPT issue.  The boot error starts with the
time out on ep0out:

[    3.264373] smsc95xx 1-1.1:1.0: usb_probe_interface
[    3.269500] smsc95xx 1-1.1:1.0: usb_probe_interface - got id
[    3.275543] smsc95xx v1.0.4
[    8.078674] smsc95xx 1-1.1:1.0: eth0: register 'smsc95xx' at usb-ehci-omap.0-1.1, smsc95xx USB 2.0 Ethernet, 82:b9:1d:fa:67:0d
[    8.091003] hub 1-1:1.0: state 7 ports 5 chg 0000 evt 0002
[   13.509918] usb 1-1.1: swapper/0 timed out on ep0out len=0/4
[   13.515869] smsc95xx 1-1.1:1.0: eth0: Failed to write register index 0x00000108
[   13.523559] smsc95xx 1-1.1:1.0: eth0: Failed to write ADDRL: -110
[   13.529998] IP-Config: Failed to open eth0


-Frank