Re: [PATCH] serial 8250: tighten test for using backup timer

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 26 Aug 2008 10:45:34 -0700
David Brownell <david-b@pacbell.net> wrote:

> > > Also, how serious is the problem which is being fixed here?  It
> > > _sounds_ like it's of the "fatal for people who have that hardware"
> > > variety, in which case we should get this into 2.6.27 and probably
> > > 2.6.26.x.  Not sure about 2.5.26.x though - the patch doesn't apply
> > > there, but I didn't check whether this is due to functional changes.
> >
> > For users of this version of this particular UART IP it is fatal. From
> > looking at the git history it looks like the original patch went into
> > 2.6.26 so it might also affect that kernel.
> 
> Second that:  serial-8250-tighten-test-for-using-backup-timer.patch
> (from MMOTM) in mainline sooner-not-later seems right.

ok, if you think so...

I still have an unanswered question out there about the init_timer()
handling in that area of the driver but afaict this patch didn't make any
of it worse than it already is.

> My own exposure to this is that the UART on DaVinci hardware, which
> TI allegedly derived from its original 16550 logic, has periodically
> gone from working to unusable with the mainline 8250.c ... and back
> and forth a bunch.  Currently it's "unusable", a regression from some
> previous versions.  With this patch from Alex, it's usable.
> 
> Of course there are a bunch of arch/arm/mach-davinci patches needed
> to make that platform more functional in mainline.  I expect they'll
> probably merge in the 2.6.28-rc0 window.  Meanwhile, running out of
> ramdisk with a serial console should at least work right!  :)
>