6.0-CURRENT SNAP004 hangs on amr (patch)

Scott Long scottl at samsco.org
Sat Sep 10 22:38:30 PDT 2005

M. Warner Losh wrote:
> In message: <43236E04.4020208 at samsco.org>
>             Scott Long <scottl at samsco.org> writes:
> : Thanks for the invesitgative work.  I strenously objected to this change
> : when it went in, and this kind of problem is precisely the reason why.
> : Turning off device power on the PCI bus willy-nilly is such an 
> : incredibly bad idea, even if the hope with it is to get a few extra 
> : minutes of battery life on a laptop.
> It is *NOT* an incredibly bad idea.  It is suggested by the standards,
> and is done by other OSes, including Windows.  I know you don't like
> it, but it is very beneficial in many circumstances.  It helps with
> heat issues as well as power consumption.

One more question.  Where exactly have you measured the effects here? 
Can you quantify how much the heat and/or power savings are on a
particular computer with this strategy in use?

> : I worked around this problem with the AAC devices, but I don't know if
> : the AMR devices can be worked around the same way.  I've asked Warner in
> : private to back out the change.  If he refuses, then I'm afraid that 
> : you'll need to remember an undocumented workaround, or find another OS.
> I've said before that the right fix is to fix the device drivers that
> have knowledge of these split devices.  I still stand by that
> assessment.
> So far only two drivers have been affected (amr and aac).  I'm
> disinclined to change it because of those two devices.

And I'm tired of cleaning up after your mess simply because I happen
to care about making a working OS.

> However, I'll start thinking about this in detail and reconsider it
> after some thought.  There may be a better workaround.
> Warner

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