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

From: Will Newton
Date: Mon Sep 01 2008 - 09:37:12 EST


On Tue, Aug 26, 2008 at 6:58 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 26 Aug 2008 10:45:34 -0700
> David Brownell <david-b@xxxxxxxxxxx> 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.

Any update on this situation? I'd really like this patch to get into 2.6.27.

Let me know if there's any further information you need.

Thanks,

>> 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! :)
>>
>
>
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