Re: Matching semantics for version numbers....

[Matthew Dharm <mdharm-usb@one-eyed-alien.net>]

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On Tue, Mar 20, 2001 at 10:12:09PM -0800, David Brownell wrote:
> Hi Matt,
> 
> Two comments come to mind:
> 
> (1) Is it correct that changing this would involve no more than:
> 
> * Linux 2.4.? kernel updates:
>     - drivers/usb/usb.c ... usb_match_id()
>     - drivers/usb/ibmcam.c ... uses range matching

I'm not certain if this range-matching is done correctly for < > or if it
thinks <= and >=, but assuming it's "working" now, yes, it would need
changing.

>     - drivers/usb/storage/unusual_devs.h ... lots of ranges

This wouldn't need updating -- it's actually improperly coded right now
with the assumption of <= and >= (which was how my custom matching code
worked).

> * Hotplug scripts
> * "usbmodules"

I'm not sure what you mean by this item.

> * No spec/documentation (yet)

Other than my comments above, yes, that should be all the changes.

> Distributions would need to get all those updates at once;
> I don't know how much of a problem that'd be, except
> that if there's no coordination then it'll be painful.  If it
> happens, this should all be ready at the same time.  (Not
> like the original match_flags patch ... though goofing this
> up would break less, since "modutils" will still work.)

AFAICT, yes.  Having one part of the patch (assuming the 2 kernel files
count as one "part") doesn't break anything.

> (2) For some reason my preference in this area would
> be to use "low <= value < high" range specs rather the
> current "low < value < high" or "low <= value <= high".
> 
> That's just a better match to how I normally think about
> such ranges -- not a huge deal, but it seems like Jeff
> Ozvold had a similar thought.  So maybe I'm not alone
> in thinking about those bcd version codes that way.

Someone mentioned this to me in a private e-mail... it seems reasonable, as
then range checks can be 0.00 -- 3.00, and 3.00 -- 9.99 with no overlap.
Tho, it _must_ be well documented that the low and high parameters are
matched slightly differently.

Matt

-- 
Matthew Dharm                              Home: mdharm-usb@one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

Ye gods! I have feet??!
					-- Dust Puppy
User Friendly, 12/4/1997

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