Messages in this thread | | | Date | Mon, 28 Jun 2004 02:14:39 +0100 | From | Russell King <> | Subject | Re: [PATCH 2.6] Altix serial driver |
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On Sun, Jun 27, 2004 at 05:33:11PM -0700, Chris Wedgwood wrote: > On Sun, Jun 27, 2004 at 07:24:34PM -0500, Erik Jacobson wrote: > > Maybe you can help me clear it up then. When I feed serial core the > > name ttyS with TTY_MAJOR and minor 64, the registration fails. If I > > disable 8250 in the kernel config, the registration works for us. > > I'm not sure why the 8250 code reserves/registers ttyS0 on Altix when > do such hardware exists. I vaguely recall patching it to prevent this > in a hacky way. > > I would like to know why the 8250 code is registering a driver for > hardware that doesn't exist and see that fixed.
It's the way its always been done, and the way the tty layer works. You register a range of ttys that you're going to be driving, and you own those ttys whether or not you actually have hardware for them.
You can't say "ok, I have ttyS1 and ttyS3, I'll leave ttyS0 and ttyS2 available for someone else to use" because the tty layer just doesn't work like that. It has the notion of a single driver for a range of non-overlapping ttys.
Yes, it would be nice to get rid of that limitation, but we're in a stable kernel series and the tty layer doesn't have a maintainer to do the work...
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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