Re: Call for testing: emu10kx driver for Creative sound cards

From: Scott Long <scottl_at_samsco.org>
Subject: Re: Call for testing: emu10kx driver for Creative sound cards
Date: Tue, 23 May 2006 12:36:16 -0600

> Warner Losh wrote:
> > From: Scott Long <scottl_at_samsco.org>
> > Subject: Re: Call for testing: emu10kx driver for Creative sound cards
> > Date: Tue, 23 May 2006 10:08:15 -0600
> > 
> > 
> >>Dag-Erling Smørgrav wrote:
> >>
> >>>Alexander Leidinger <Alexander_at_Leidinger.net> writes:
> >>>
> >>>
> >>>>Quoting des_at_des.no (Dag-Erling Smørgrav) (Tue, 23 May 2006 14:26:58 +0200):
> >>>>
> >>>>
> >>>>>Yuriy Tsibizov <Yuriy.Tsibizov_at_gfk.ru> writes:
> >>>>>
> >>>>>
> >>>>>>2. Complete mixer support. Some controls that can't fit into OSS
> >>>>>>mixer are available as sysctl under debug.emu10kxX.
> >>>>>
> >>>>>That is not the correct place for it.  Please use the device's sysctl
> >>>>>context (obtained with device_get_sysctl_ctx())
> >>>>
> >>>>This was based upon a suggestion by me. We want to get rid of most
> >>>>sound related syscalls (at least those which belong into the realm of
> >>>>the user, and not into the realm of the administrator). Until we have
> >>>>an application and an interface, we have to life with the sysctls, but
> >>>>to let the users know that this is not an interface but a temporary
> >>>>workaround, it's put into the debug MIB. I hope we will not ship
> >>>>7.0-RELEASE with any such sysctl (any help appreciated).
> >>>
> >>>
> >>>Regardless, device-specific sysctl knobs belong in the individual
> >>>device's sysctl context, which automatically places them in the
> >>>correct location in the dev tree and automatically destroys them when
> >>>the device is destroyed.  Please do not create further precedent for
> >>>breaking this rule, no matter how good your intentions.
> >>>
> >>>DES
> >>
> >>The problem is that Alexander wants these sysctls to only be temporary.
> >>Recall that big thread from a month or two ago about treating sysctls
> >>as an API, and how there was heavy disagreement over how to define
> >>"stable" sysctls that apps could depend on?  If a temporary set of 
> >>sysctls get put under the dev tree, then it risks becoming permanent,
> >>which is not what Alexander wants.  So, either we need to decide what
> >>parts of the sysctl to define as stable, like I asked for in the 
> >>previous thread, or we need to pretend that it's not a problem that we
> >>should address, and let you and Alexander continue to argue over the
> >>'correct place'.
> > 
> > 
> > Then put them under the right place, but create a subtree that's "tmp"
> > 
> > In general, drivers should avoid using the debug.* space.
> > 
> > Warner
> 
> But that's the problem.  You just announced a rule that is in conflict
> with rules that others have announced.  All I asked for was for the 
> rules to be decided on and published, and I got pushback from people
> who said either that all sysctls are part of the API, or that no rules
> should exist and that everyone should just use careful judgement, so
> long as their judgement is correct.  Both of these stances are absurd.

Drivers have no business using debug.* anymore.  They should migrate
to the new interface that has already been in use, like DES said.
Putting them in debug* doesn't make them any more or less permanant.
The driver should document what is published and isn't published
(approved, etc) in its man page.  In this case, adding a list of the
'blessed' sysctls to the appropriate man page with a warning that says
that all others are for the convenience of the driver writer and may
disapper would solve the problem.  Putting them under 'temp' or 'tmp'
would also be a strong hint, but isn't completely necessary.

Warner