Re: [BUG] panda board locks up on boot

Re: [BUG] panda board locks up on boot

[Nishanth Menon]

On 01/27/2013 08:12 AM, Paolo Pisati wrote:
> On Fri, Jan 25, 2013 at 08:43:15AM +0000, Mats Liljegren wrote:
>> Hi Steven,
>>
>> Do you have CONFIG_CPU_FREQ enabled? As I posted earlier in linux-kernel forum ("Failed booting PandaBoard ES with Linux 3.8 RC4" two days ago) my PandaBoard ES hangs while booting with this option enabled. It works fine without it. I have not bisected it down to a single commit though.
>
> glad i'm not the only one who hit this problem:
>
> "3.8rc4+ and cpu_freq omap: hangs, oopses, etcetc"
>
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg83693.html
>

Support for TPS is not yet in mainline kernel. you may want to do:

you could try running 'mw.w 0x4A31E05A 0x1' before bootm in u-boot -> 
This will hack the pad of panda ES pin mean for controlling TPS voltage 
register (again a kernel bug where the GPIO block setup by bootloader 
got reset).

CPUfreq needs both voltage and frequency scaling to work and without 
support of the TPS voltage scaling on vdd_MPU, you are stuck at boot 
voltage, and just scaling frequency. with the not-enough boot voltage, 
moving to higher frequencies can/will result in unpredictable behavior.

---
Regards,
NM

RE: [BUG] panda board locks up on boot

[Mats Liljegren]

> From: Nishanth Menon [mailto:menon.nishanth@gmail.com]
> Sent: den 27 januari 2013 15:34
> To: Paolo Pisati
> Cc: Mats Liljegren; Tony Lindgren; LKML; Steven Rostedt; Igor Grinberg;
> Russell King; Venkatraman S; linux-arm-kernel; linux-omap
> Subject: Re: [BUG] panda board locks up on boot
> 
> On 01/27/2013 08:12 AM, Paolo Pisati wrote:
> > On Fri, Jan 25, 2013 at 08:43:15AM +0000, Mats Liljegren wrote:
> >> Hi Steven,
> >>
> >> Do you have CONFIG_CPU_FREQ enabled? As I posted earlier in linux-
> kernel forum ("Failed booting PandaBoard ES with Linux 3.8 RC4" two days
> ago) my PandaBoard ES hangs while booting with this option enabled. It
> works fine without it. I have not bisected it down to a single commit though.
> >
> > glad i'm not the only one who hit this problem:
> >
> > "3.8rc4+ and cpu_freq omap: hangs, oopses, etcetc"
> >
> > http://www.mail-archive.com/linux-
> omap@vger.kernel.org/msg83693.html
> >
> 
> Support for TPS is not yet in mainline kernel. you may want to do:
> 
> you could try running 'mw.w 0x4A31E05A 0x1' before bootm in u-boot -> This
> will hack the pad of panda ES pin mean for controlling TPS voltage register
> (again a kernel bug where the GPIO block setup by bootloader got reset).
> 
> CPUfreq needs both voltage and frequency scaling to work and without
> support of the TPS voltage scaling on vdd_MPU, you are stuck at boot
> voltage, and just scaling frequency. with the not-enough boot voltage,
> moving to higher frequencies can/will result in unpredictable behavior.
> 
> ---
> Regards,
> NM

Thanks for the suggestion. Unfortunately it didn't make any difference for me, neither did an upgrade to 3.8-rc5. I guess I have to wait for the TPS support to hit mainline kernel.

Regards
Mats