On Fri, Feb 11, 2011 at 11:18:50PM +0100, Michael Biebl wrote: > Hi Josh > > On 11.02.2011 21:44, Josh Triplett wrote: > > Package: pm-utils > > Version: 1.4.1-6 > > Severity: normal > > > > > > (I'd argue more generally against running those hooks on *any* device, > > but this seems like the right place to start, and it solves my immediate > > problem. :) ) > > Generally I agree with you. It is hard to strike a balance between saving > power > and stability. But we try hard to do so. > Have you read further in the changelog: > ... > * debian/rules: Remove harddrive power hook, this causes excessive hard disk > spindown on a lot of machines. The hdparm package already ships > ... > * Add 14-disable-sata-alpm.patch: Disable SATA link power management by > default, as it still causes disk errors and corruptions on many hardware. > (LP: #539467)
I did see both of those, but both just work around hardware bugginess. The other hooks I mentioned have the much more serious issue of delaying writeback of user data, risking data loss if the system never gets a chance to write it. > So, we already disabled those hooks where we know it can cause problems. > Regarding laptop-mode: Does it cause any problems / does it have negative side > effects on SSD? Yes: it delays the writeback of data, putting it at risk. laptop-mode tries to avoid spinning up the disk, but when the disk doesn't spin that no longer matters. SSDs idle very effectively when they don't have work to do, and don't need a spin-up and spin-down period; they sleep when idle much like CPUs do. So, delaying spin-up doesn't actually lead to any significant power savings (unlike with a spinning disk), but still incurs the same risk. - Josh Triplett -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
