Messages in this thread | | | Date | Tue, 08 Aug 2006 14:40:15 -0400 | From | Bill Davidsen <> | Subject | Re: 2.6.18-rc2, problem to wake up spinned down drive? |
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Tejun Heo wrote:
> Harald Dunkel wrote: > >> Tejun Heo wrote: >> >>> Pavel Machek wrote: >>> >>>>> echo 1 > /sys/bus/scsi/devices/1:0:0:0/power/state >>>> >>>> Really? I thought power/state takes 0/3 (for D0 and D3) >>> >>> Yes, of course. My mistake. Sorry about the confusion. The correct >>> command is 'echo -n 3 > /sys/bus/scsi/devices/x:y:z:w/power/state'. >>> >> >> (Sure? :-) > > > The sleeping part is correct. That will make libata put the disk to > sleep. > >> Now this did not work at all. The '-n 3' was probably >> correct, but when I tried to access the disk, then it >> did not spin up again (I waited for 5 minutes). There >> was no message on the console, either. >> >> But I could not reproduce this problem. >> >> How do I monitor that the disk spins down and up? > > > But the waking up part isn't. You need to issue wake up explicitly by > doing 'echo -n 0 > /sys/...' I've been a complete idiot in this > thread. Please excuse me. :-( > > I think the solution to your problem is adjusting command timeout to > more reasonable values which should make the problem more bearable. > It'll take some time to figure out how to make timeouts more > intelligent without breaking support for slow devices. I'll work on > that.
Tejun, would it be possible and sensible to either let the user tune this per-drive, or to have the kernel note how long {something} takes and auto-tune to that? As you said, the issue is not breaking slow devices.
-- bill davidsen <davidsen@tmr.com> CTO TMR Associates, Inc Doing interesting things with small computers since 1979
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