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Date:      Sat, 20 Nov 2004 20:12:55 -0500
From:      "Alexandre \"Sunny\" Kovalenko" <Alex.Kovalenko@verizon.net>
To:        Nate Lawson <nate@root.org>
Cc:        acpi@FreeBSD.org
Subject:   Re: PATCH: power down acpi and pci devices in suspend/resume
Message-ID:  <1100999575.747.10.camel@RabbitsDen>
In-Reply-To: <419EF7AD.8050007@root.org>
References:  <419EF7AD.8050007@root.org>

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On Fri, 2004-11-19 at 23:52 -0800, Nate Lawson wrote:
> The attached patch implements setting power states for ACPI (i.e. ISA) 
> and PCI devices in the suspend/resume path.  This may help with some 
> problems; it's quite likely it may introduce problems.  That's why I'd 
> like it tested.  If you have a system that suspends/resumes ok or that 
> fails, please try it.  The likely failure case is a hang in suspend or 
> resume or a device that doesn't work afterwords.  It's pretty 
> heavy-handed, only avoiding changing power for serial ports since those 
> are known to cause a hang (which can possibly be fixed by making 
> sio/uart more aware of power states.)  I suspect devices like PCI 
> bridges may have problems with power changes.
> 
> If you have problems, please let me know the info it prints before the 
> hang so I can figure out what the problem device is.
> 
> -Nate

First, the disclaimer: on my system (Averatec 3150H) entering S3 state
only works if I take out infinite loop in acpi_wakeup.c. I don't know
whether it still technically enters S3 state or not, but it surely
powers down everything in sight, including back light and PCMCIA
controller. Battery life (by very unscientific measurements) doubles,
which makes me believe, that it is not quite S3 ;)

This said, with this patch, only observable difference is that screen
goes all-white right before switching off back light and is all-white
after resume, switching to normal display shortly afterward. I could not
judge whether this behavior is of any interest to you and what
additional info (if any) might be required. If there is any, please, let
me know and I will be happy to oblige.
---
Alexandre "Sunny" Kovalenko.



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