Re: 8250.nr_uarts broken in 3.7

Josh Boyer
2013-03-08T01:02:28Z

On Fri, Mar 08, 2013 at 07:12:42AM +0800, Greg Kroah-Hartman wrote:
> On Thu, Mar 07, 2013 at 04:14:27PM -0500, Josh Boyer wrote:
> > On Thu, Mar 07, 2013 at 02:10:05PM -0500, Josh Boyer wrote:
> > > On Thu, Mar 07, 2013 at 08:07:23PM +0100, Jiri Slaby wrote:
> > > > On 03/07/2013 07:56 PM, Josh Boyer wrote:
> > > > > commit 835d844d1a28efba81d5aca7385e24c29d3a6db2
> > > > > Author: Sean Young <sean@mess.org>
> > > > > Date: Fri Sep 7 19:06:23 2012 +0100
> > > > >
> > > > > 8250_pnp: do pnp probe before legacy probe
> > > > >
> > > > > but that is simply moving code around.
> > > >
> > > > Hi, not quite. Does it still happen when you revert that one on the top
> > > > of 3.[789]*?
> > >
> > > That was going to be my first attempt. I'll let you know how it goes.
> >
> > Yes, reverting just 835d844d1 on top of 3.7.0 fixes it. I also see why
> > now. That commit changed the module name from 8250 to 8250_core in the
> > makefile, so clearly 8250.nr_uarts = 16 isn't going to get parsed.
> > Adding 8250_core.nr_uarts = 16 seems to work fine. This wasn't
> > immediately obvious because the whole thing is built-in and not a
> > module. Thankfully, looking in /sys/modules/ still works and that
> > showed up pretty clearly.
> >
> > So I guess this isn't really a break in functionality as much as it's a
> > driver rename. Not sure if it's worth fixing in some form or not.
>
> Yes it needs to be fixed, we shouldn't break userspace stuff like that.
> Patches gladly accepted.

OK... well I don't think renaming it back to 8250 is going to actually
work. It's already been renamed for 2 releases now, and a renaming
isn't appropriate for 3.8.y.

I don't remember exactly, but I don't think simply adding a modalias to
8250 will work either.

So basically, the only way to fix this that I can see is to create a
new, additional module parameter or something similar that parses
"8250.nr_uarts". Is that what you had in mind?

josh