Date: Sat, 28 Feb 2004 22:09:58 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: John Baldwin <john@baldwin.cx> Cc: Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?= <des@des.no> Subject: Re: per-device sysctls Message-ID: <20040228220602.K6048@gamplex.bde.org> In-Reply-To: <200402271007.43299.john@baldwin.cx> References: <xzpk729lnq7.fsf@dwp.des.no> <xzp7jy9lmnf.fsf@dwp.des.no> <20040227230124.D2469@gamplex.bde.org> <200402271007.43299.john@baldwin.cx>
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On Fri, 27 Feb 2004, John Baldwin wrote: > On Friday 27 February 2004 07:16 am, Bruce Evans wrote: > > On Thu, 26 Feb 2004, Dag-Erling [iso-8859-1] Sm=F8rgrav wrote: > > > "M. Warner Losh" <imp@bsdimp.com> writes: > > > > How is this different than the sysctl stuff that already exsists fo= r > > > > this and is accessed by devinfo? > > > > > > 1) it is immensely easier to access > > > > > > 2) it gives drivers a well-defined place to put their per-device > > > sysctl variables - devinfo doesn't address that issue at all > > > > Only broken drivers use sysctl variables. ioctl(3) is a much better > > interface that sysctl(3) for accessing per-device info. sysctl(8) is > > a better interface than ioctl(8) for handling the few device control > > things that can be done in a generic way, but this is only because > > there are so few such things that ioctl(8) doesn't exist. > > Note that ioctl's act on dev_t devices, not on device_t devices. We have= two > distinct notions of a device right now: physical hardware devices (new-bu= s) > and UNIX file devices (entries in /dev). You can ioctl the latter, but n= ot > necessarily the former. I think (2) means dev_t devices. I agree that a separate mechanism (but no= t 2) is needed for device_t devices. Bruce
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