omap4-panda-es boot issues with v3.15-rc4

[Tony Lindgren]

* Kevin Hilman <khilman at linaro.org> [140508 08:40]:
> On Thu, May 8, 2014 at 8:31 AM, Kevin Hilman <khilman at linaro.org> wrote:
> > Roger Quadros <rogerq at ti.com> writes:
> >
> >> Hi,
> >>
> >> Nishant pointed me to a booting issue with omap4-panda-es on linux-next but I'm observing
> >> similar issues, although less frequent, with v3.15-rc4 as well.
> >>
> >> Configuration:
> >>
> >> - kernel v3.15-rc4 or linux-next (20140507)
> >> - multi_v7_defconfig with LEDS_TRIGGER_HEARTBEAT and LEDS_GPIO enabled
> >> - u-boot/master       173d294b94cf
> >>
> >> Observations:
> >>
> >> - Out of 10 boots a few may not succeed and hang midway without any warnings. Heartbeat LED stops.
> >> e.g. http://www.hastebin.com/ebumojegoq.vhdl
> >>
> >> - Hang more noticeable on linux-next (20140507) than on v3.15-rc4
> >
> > I've beeen noticing the same thing for awhile with my boot tests.  For
> > me, next-20140508 is failing most of the time now.
> >
> >> - Hang more noticeable with USB_EHCI_HCD enabled but hang observed even without USB_EHCI_HCD.
> >> Maybe related to when high speed interrupts occur in the boot process.
> >>
> >> - On successful boots following warning is seen
> >> [    4.010375] gic_timer_retrigger: lost localtimer interrupt
> >>
> >> - On successful boots heartbeat LED stops blinking after boot process and left idle. LED can remain stuck in
> >> ON state as well. It does blink again when doing activity on console.
> >>
> >> Workaround:
> >>
> >> - Disabling CPU_IDLE or even just disabling C3 (MPU OSWR) seems to fix all the above issues.
> >>
> >> I don't really know what exactly is the issue but it seems to be specific to OMAP4, GIC, MPU OSWR.
> >
> > I can confirm that disabling CONFIG_CPU_IDLE seems to make the problem
> > go away.  Hmm....
> 
> Another finger pointing in the same direction: omap2plus_defconfig +
> CONFIG_CPU_IDLE=y also fails to boot rather consistently in today's
> -next.

Booting today's next with multi_v7_defconfig (so cpuidle enabled) on
omap4 sdp seems to boot reliably. And it's not producing these:

gic_timer_retrigger: lost localtimer interrupt 

while panda is producing those errors like Roger mentioned.

It seems that the USB networking is the main difference between
omap4 sdp and panda?

Regards,

Tony