On Sat, Mar 2, 2013 at 9:49 PM, intrigeri <intrigeri@???> wrote:
> If these settings were seriously
> wrong, I guess we would have seen quite a lot of bug reports in Debian
> during the Wheezy development cycle.
Like these? Just a few examples.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=684241
https://bugs.launchpad.net/ubuntu/+source/hdparm/+bug/913050
> Given we have not, I'm quite
> confident these settings are good enough... until I'm shown why this
> is wrong, which Maxim is apparently willing to do.
Well, I experienced the problem with -B127 first-hand on a laptop, the
result was equivalent to -B1 below.
> I guess you're talking of this part of the commit:
>
>> +# NOTE: many laptop drives support only values 1, 128, 254, 255,
>> +# with 1 resulting in immediate spindown after each access
>
> ... that apparently explains why you moved away from using 127 on AC
> power and 1 on battery.
That information comes from some extensive online searching —
unfortunately, I don't have the links anymore (this happened 1.5 years
ago). Hdparm man page is seriously wrong — -B128 does permit spindown
(at least on hardware that I tried), when combined with -S. The
discussions I found at the time of the commit had extensive
information on that, with NOTE above being a short summary.
>> Having 254 for everyone on AC is unreasonable, in my opinion.
>
> I concur with Alan: would you please share some insight about why this
> is unreasonable?
I don't think hard drives will ever spin down with -B254, even with -S
(again, it has been some time, so I might be wrong — I think the
laptop on which I saw problems with -B127 never spun down with -B254,
so this might not be universally true/untrue). Given that the people
recommending use of -B254 don't really understand the issue (e.g.,
-B128 would fix the issues with a drive constantly going idle from due
to -B127 just the same, and sometimes the problems result from using
-B255 with older hdparm versions that didn't treat the parameter
correctly), I would say that -B128 is the correct value to use, when
-S is also specified (which laptop-mode does for IDLE_TIMEOUT
parameters).
--
Maxim Kammerer
Liberté Linux:
http://dee.su/liberte
