Gopinath, Thara wrote:
-----Original Message-----
From: linux-omap-ow...@vger.kernel.org
[mailto:linux-omap-ow...@vger.kernel.org] On Behalf Of Mike
Rapoport
Sent: Friday, July 30, 2010 12:41 AM
To: Mikko Rapeli
Cc: linux-omap@vger.kernel.org; Turquette, Mike; sa...@linux.intel.com
Subject: Re: [PATCH v2] twl4030 reboot workaround
Hi
On Thu, Jul 29, 2010 at 9:41 AM, Mikko Rapeli
<ext-mikko.rap...@nokia.com> wrote:
From: Mikko Rapeli <ext-mikko.rap...@nokia.com>
Original patch: http://marc.info/?l=linux-omap&m=126522625032441&w=2
"Removes TWL4030 sleep script prior to rebooting, only on OMAP3. This is
necessary since DPLL3 reset causes SYS_OFFMODE pin to go low, resulting
in the sleep script being executed on TWL4030. This usually results in
VDD1 & VDD2 voltage collapse while ROM code is executing, followed by an
MPU Watch Dog reset or worse, an irrecoverable hang."
I had a similar issue when my system hanged on hard reset when there
was a TWL sleep script installed.
The workaround I've found was to install the sleep script immediately
before entering the suspend state and remove the script on the resume
path.
If you think that such approach is appropriate I can send a patch.
How do you hit the off state(Vdd's at 0 V) in the idle path then? Or do you do
this every
time in the idle thread also?
I do not think it is appropriate to add/remove the sleep script
before/after every OFF mode case. The script should be programmed once
and left alone EXCEPT in the case of warm reset.
If there are other corner cases where SYS_OFFMODE goes low, then we
should cover those with similar fixes to the warm reset fix, but in
general I think the policy should be to leave the scripts alone once
programmed
Dynamically programming/removing the scripts around OFF transitions
increases software overhead for those transitions even more which is
very undesirable.
Mike
Regards
Thara
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