Re: 3.1[34]: omap4: panda: hang on reboot?

[Tony Lindgren <tony@atomide.com>]

* Paolo Pisati <p.pisati@gmail.com> [140331 15:00]:
> On Thu, Mar 27, 2014 at 06:54:14PM +0100, Paolo Pisati wrote:
> > I've been experiencing hangs on reboot on two different panda boards (es rev1
> > and vanilla rev a1) with v3.14-rc8 (but reproducible in 3.13 too):
> > 
> > toolchanin: gcc version 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu7)
> > 
> > the config is a multi_v7_defconfig plus a couple of codepages:
> > 
> > http://people.canonical.com/~ppisati/omap4_reboot_hangs/config
> > 
> > a prebuilt zImage is available here:
> > 
> > http://people.canonical.com/~ppisati/omap4_reboot_hangs/zImage
> > 
> > sometimes i can hit this two times in a row, others it's a bit less
> > frequent - put this into your crontab and let it go:
> > 
> > */5 * * * *       /bin/date >> /reboot.log && /sbin/reboot
> > 
> > it never passed 2hrs of reboot cycles.
> > 
> > I already tried different u-boots but that doesn't make any difference,
> > am i the only one experiencing this issue?
> 
> i bisected it down to this commit:
> 
> commit e002264f7e45d7661b237045577052fd0b40f89c
> Author: Balaji T K <balajitk@ti.com>
> Date:   Mon Oct 21 00:25:18 2013 +0530
> 
>     mmc: omap_hsmmc: Fix pbias_disable for omap4
>     
>     pbias_disable is set to protect the mmc pbias i/o cells in DT boot
>     by preventing voltage switch. Currently pbias_disable is enabled only
>     for omap3 and not for omap4 due to reg_offset difference of 0x100.
>     Enable pbias_disable for omap4+ too by using res->start
>     which does not include the reg_offset.
>     
>     Signed-off-by: Balaji T K <balajitk@ti.com>
>     Signed-off-by: Chris Ball <cjb@laptop.org>
> 
> with this commit reverted, i can reboot in a loop for hours without any problem,
> while if i keep this patch, my pandas don't survive more that two hours (again,
> it's really random as it could hang a couple of times in a row and then work
> like a charm for ten reboots straight).
> 
> Any idea? does it ring any bell?

Balaji, do you have a fix for this one?

Tony