Re: [PATCH] Fix typo in pmac_zilog

[Benjamin Herrenschmidt]

On Sun, 2004-05-30 at 16:42, David S. Miller wrote:
> On Fri, 28 May 2004 13:40:55 +1000
> Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:
> 
> > This patch fixes a typo preventing channel B from working on the Rx
> > path of pmac zilog (never calling tty_flip_*). I think I never tested
> > channel B :)
> 
> Ben, why do you do the tty_flip_buffer_push() outside of
> the port lock?  Just because it's expensive and therefore
> this decreases the lock hold time, or is there some deadlock
> issue?
> 
> Sounds like I should make the change to sunzilog :-)

There is a deadlock issue. I triggered once when I had a bug where the
driver was flooding the input with zero's. All serial drivers seem to be
affected. Apparently, tty_flip_* may call back into your write() routine

Ben.


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