Messages in this thread | | | Date | Sat, 11 May 2013 00:29:55 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [RFC 1/8] serial:st-asc: Add ST ASC driver. |
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On Wed, May 08, 2013 at 09:36:13AM -0700, Greg KH wrote: > On Wed, May 08, 2013 at 06:31:48PM +0200, Arnd Bergmann wrote: > > On Wednesday 08 May 2013, Greg KH wrote: > > > > just mention there is not hardware reason to not use the generic ttySx > > > > in place of ttyAS as we have only one IP that handle serial on this > > > > family of SoC > > > > > > > > personally I'll switch to ttySx > > > > > > Great, then you can use the same major/minor range as well, so there's > > > no more objection from me about this :) > > > > Does that work these days when you have kernel with multiple built-in > > uart drivers? > > It "should", as the major/minor registration should only happen when the > hardware is found, but I haven't tested it out, so I can't say for sure.
serial stuff has never operated like that. More specifically, it's a limitation with the tty stuff that the way stuff works is that a tty driver can only drive a single bunch of contiguous minor numbers. No interleaving is allowed.
That limitation has existed for years, and I don't see it going away. As long as that limitation exists, you can only ever have one serial driver driving a set of contiguous minor numbers.
There has been an attempt to "work around" this by making the 8250 driver "special" which was a complete hack to get it to work. That was while I maintained this stuff and I outright refused to make one serial driver magically special.
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