From: Josh Karabin <gkarabin@vocollect.com>
To: Peter Barada <peterb@logicpd.com>
Cc: "Syed Mohammed, Khasim" <khasim@ti.com>,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: Re: JTAG debugging of the kernel
Date: Fri, 15 Aug 2008 14:57:31 -0400 [thread overview]
Message-ID: <48A5D19B.1050407@vocollect.com> (raw)
In-Reply-To: <1218823096.24975.108.camel@blackhole>
Peter Barada wrote:
> On Fri, 2008-08-15 at 23:04 +0530, Syed Mohammed, Khasim wrote:
>>> -----Original Message-----
>>> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Peter
>>> Barada
>>> Any suggestions on what can cause the JTAG to stop working after the
>>> kernel starts?
>>>
>> I think you should disable Power Management. Which kernel are you using now?
>
> 2.6.22.18. I'm planning to move to 2.6.26 after the dust settles...
>
> I'll try w/o power management, but any idea why power management might
> affect JTAG?
The guy I share an office with (who's out on vacation) worked through
this with their tech support, who suggested replacing WFI instructions
with NOPs.
Look at cpu_v7_do_idle in arch/arm/mm/proc-v7.S. Changing the WFI to a
NOP did the trick for him.
Presumably power management was off, but even WFI (wait for interrupt)
put the CPU in a state that wasn't handled by the BDI firmware at the
time. I'm not sure if they resolved the issue in a later firmware
update or not. We didn't think the workaround was worthy of a Kconfig
option - hopefully updated firmware for the BDI box will address the issue.
- Josh
next prev parent reply other threads:[~2008-08-15 18:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-15 15:03 JTAG debugging of the kernel Peter Barada
2008-08-15 17:34 ` Syed Mohammed, Khasim
2008-08-15 17:58 ` Peter Barada
2008-08-15 18:57 ` Josh Karabin [this message]
2008-08-18 18:47 ` Peter Barada
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