Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: [stable] A patch in 2.6.27.9 caused device names to change | Date | Wed, 4 Feb 2009 08:28:44 +0100 |
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Am Wednesday 04 February 2009 01:03:42 schrieb Greg KH: > On Tue, Feb 03, 2009 at 09:50:11AM -0500, Dan Williams wrote:
> > For a long time we've been operating under the assumption that mobile > > broadband devices should be driven by option and sierra, since those > > drivers had the necessary buffering optimizations to support > > higher-speed mobile broadband devices. > > Who is "we" here? Not me :)
We currently have three drivers that can handle high speed serial connections in USB, option, sierra and cdc-acm.
> > That was true at least up until 2.6.24. > > It all depends on the type of device. If it says it is a cdc-acm modem, > by all means, let that driver handle it, don't try to bind it to a > different driver (that way lies races and madness...) > > > Furthermore, up until this point, I have not seen mobile broadband > > adapters (that aren't cellphones connected via USB) that *are* CDC-ACM > > compliant. Everything previously has advertised proprietary interfaces, > > some of which are serial ports and some of which are not. > > Probably because we never see those devices being reported, because they > "just work" with no interaction from us.
As far as I can tell, devices implementing the class specification are new and still quite rare. This is probably related to the relative newness of the WHC specification.
> > Plus, are we expected to keep device names stable these days? cdc-acm > > is the catch-all driver, but if that driver is more "generic" and a > > better driver is found, can we not update IDs just because the device > > name may change?
There is no such thing as a better driver for a device that correctly implements the class specification than the class driver. You haven't seen complaints about cdc-acm's performance in a long time, have you?
Regards Oliver
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