Date: Sat, 11 Dec 2004 11:40:18 -0800 From: Nate Lawson <nate@root.org> To: Tobias Roth <roth@iam.unibe.ch> Cc: freebsd-acpi@freebsd.org Subject: Re: suspend status Message-ID: <41BB4D22.6080205@root.org> In-Reply-To: <20041211092048.GA15338@droopy.unibe.ch> References: <20041211014613.GK695@hsc.fr> <41BA61C6.9080903@centtech.com> <20041211092048.GA15338@droopy.unibe.ch>
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Tobias Roth wrote: > On Fri, Dec 10, 2004 at 08:56:06PM -0600, Eric Anderson wrote: > >>Refigure your math - if 100% cpu means 3hrs 18 minutes of runtime left, >>then that about 200 minutes of runtime. So 1% equals 2 minutes of >>runtime roughly. So, you suspend - and wait up 90 minutes later. If it >>would have been running like normal, it would eat up 1% per 2 minutes, >>so about 45% of your battery - but it didn't, it only ate up 20%. So >>ath that rate, it was using less than half the power as when in >>non-suspend mode. > > how long would the same laptop/battery survive when suspended from > windows? i always had in mind that a suspended laptop is supposed to > live for more than a day, which clearly is not the case in your example. > > you often hear comparisons here about how much less battery windows uses > when compared to FreeBSD (or rather, how much better windows battery > saving techniques are). detailed comparisons of bsd <-> linux <-> windows > with good guesses of why the discrepancies are there would help. > > i am just trying to say that battery saving in suspend probably IS bad > in FreeBSD (as compared to the possible optimum, as windows shows it). > it's not just bad math in the above example. I'd like it if people took the time to compare various features on windows/linux/freebsd including average temp during your normal use, battery usage, etc. Both my ThinkPads last a very long time in S3 (weeks). However, I think BIOS code handles most of the system power issues which may hide things that the OS doesn't do as well. If a single device driver doesn't properly power down a device, it may be the culprit. Such problems are hard to find, obviously. I do know that some display adapters need more magic than X is currently using. Also, bms@ pointed out that we possibly need to hook X into suspend/resume more. I started some patches for that (on my web page) but didn't get very far since I don't know the X server code and it wasn't clear that the module in question (bsd_apm) is even compiled on FreeBSD. The other thing you can try is my suspend power patch (committed in -current, patch posted recently here for 5.x). It may help since it explicitly powers down/up acpi and pci devices in suspend. -- Nate
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