Re: [9fans] Intel 815 question

Re: [9fans] Intel 815 question

[jmk]

On Mon Feb 12 05:46:23 EST 2001, gwyn@arl.army.mil wrote:
> It's actually the IDE controller light.  I think what you
> really want to know is whether Plan9 spins down disk drives
> to conserve power, which helps on a notebook computer but
> not on a desktop.  I think the answer is, No.  Note that no
> harm is done to the disk drive by leaving it spinning, and
> in fact many computer engineers think that reliability is
> enhanced thereby.

I recently added some basic power-control control to the ATA
driver:

	If supported by the unit, the standby timer may be enabled:

		% echo 'standby T'>/dev/sdC0/ctl

	where T is the standby timer period in seconds.  T must be
	between 30 and 1200, or can be 0 to disable the timer.

There are actually finer levels of control available on many
laptop drives but this was a simple way to get most of the savings.

Works great when you have 802.11b wireless and there's just no
need for the disc once the machine is booted.

--jim

Re: [9fans] Intel 815 question

[Andrew Pochinsky]

Yes, within 0.3%: BIOS (and the processor box markings) says 733MHz,
9load thinks 731. It's PIII, it that matters.

--andrew

   Do you know if the CPU speed is being correctly determined by the kernel?

   --jim

Re: [9fans] Intel 815 question

[jmk]

Do you know if the CPU speed is being correctly determined by the kernel?

--jim


On Mon Feb 12 13:25:27 EST 2001, avp@honti.mit.edu wrote:
> Looks like I found a workaround.
>
> I did some prodding over the weekend, and in addition found the
> following.  When the IDE is configured in the following way, plan9
> fails to recognize any device the second channel.
>
>   channel 1    drive 0    Maxtor 60GB drive
>   channel 2    drive 0    Toshiba DVD
>   channel 2    drive 1    Iomega Zip 250
>
> (That is in addition to not turning the access light to sdC0 ever.)
>
> Playing with /sys/src/9/pc/sdata.c shows that if DbgPROBE is orred to
> DEBUG, the kernel recognizes and happily uses all the drives (And
> barfs all over the screen with ata.... messages all the time.)  The
> real culprit seems to be the delay between IDE_DRIVE_IDENIFY and
> status reading in ataprobe():
>
> 	outb(cmdport+Command, Cedd);
> 	delay(2);
> 	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 6*1000*1000) < 0)
> 		goto release;
>
> If I increase delay between outb() and ataready() to about 500,
> everything works fine -- all devices are found and are readable, the
> light goes on and off as it should. So, to give it some margin, I
> rebuild the kernel with delay(1000) and everything seems happy now.
>
> If I remember ATA specs correctly, the IDENTIFY command requires that
> the CPU does not start polling status for 2uS after issuing the
> command, and promise that the command sets status bits in at most
> 6s. Somehow ataready() leaves the controller confused, it seems.
>
> --andrew
>
>    Andrew Pochinsky wrote:
>    >   I'm running Plan 9 on the Intel 815 chipset mb and noticed that it
>    > does not turn off the hard drive light. The problem seems to be not
>    > with the hardware (for lesser OSes do switch the light off when the
>    > disk is idle). I'm wondering if anyone else had seen such a behaviour
>    > and if it's something to worry about.

Re: [9fans] Intel 815 question

[Richard Miller]

> spins down disk drives
> to conserve power, which helps on a notebook computer but
> not on a desktop.

Even if it doesn't conserve power, it makes for a quieter office
for those of us who are not fortunate enough to have a fileserver
down the hall.  (Or in the attic: http://www.9fs.org/netpic.html )


-- Richard Miller

Re: [9fans] Intel 815 question

[Andrew Pochinsky]

Looks like I found a workaround.

I did some prodding over the weekend, and in addition found the
following.  When the IDE is configured in the following way, plan9
fails to recognize any device the second channel.

  channel 1    drive 0    Maxtor 60GB drive
  channel 2    drive 0    Toshiba DVD
  channel 2    drive 1    Iomega Zip 250

(That is in addition to not turning the access light to sdC0 ever.)

Playing with /sys/src/9/pc/sdata.c shows that if DbgPROBE is orred to
DEBUG, the kernel recognizes and happily uses all the drives (And
barfs all over the screen with ata.... messages all the time.)  The
real culprit seems to be the delay between IDE_DRIVE_IDENIFY and
status reading in ataprobe():

	outb(cmdport+Command, Cedd);
	delay(2);
	if(ataready(cmdport, ctlport, dev, Bsy|Drq, 0, 6*1000*1000) < 0)
		goto release;

If I increase delay between outb() and ataready() to about 500,
everything works fine -- all devices are found and are readable, the
light goes on and off as it should. So, to give it some margin, I
rebuild the kernel with delay(1000) and everything seems happy now.

If I remember ATA specs correctly, the IDENTIFY command requires that
the CPU does not start polling status for 2uS after issuing the
command, and promise that the command sets status bits in at most
6s. Somehow ataready() leaves the controller confused, it seems.

--andrew

   Andrew Pochinsky wrote:
   >   I'm running Plan 9 on the Intel 815 chipset mb and noticed that it
   > does not turn off the hard drive light. The problem seems to be not
   > with the hardware (for lesser OSes do switch the light off when the
   > disk is idle). I'm wondering if anyone else had seen such a behaviour
   > and if it's something to worry about.

Re: [9fans] Intel 815 question

[Douglas A. Gwyn]

Andrew Pochinsky wrote:
>   I'm running Plan 9 on the Intel 815 chipset mb and noticed that it
> does not turn off the hard drive light. The problem seems to be not
> with the hardware (for lesser OSes do switch the light off when the
> disk is idle). I'm wondering if anyone else had seen such a behaviour
> and if it's something to worry about.

It's actually the IDE controller light.  I think what you
really want to know is whether Plan9 spins down disk drives
to conserve power, which helps on a notebook computer but
not on a desktop.  I think the answer is, No.  Note that no
harm is done to the disk drive by leaving it spinning, and
in fact many computer engineers think that reliability is
enhanced thereby.

[9fans] Intel 815 question

[Andrew Pochinsky]

Hi, 9ers,

  I'm running Plan 9 on the Intel 815 chipset mb and noticed that it
does not turn off the hard drive light. The problem seems to be not
with the hardware (for lesser OSes do switch the light off when the
disk is idle). I'm wondering if anyone else had seen such a behaviour
and if it's something to worry about.

Thanks,
--andrew