On Fri, 20 May 2022, Uwe Kleine-König wrote:
> On Fri, May 20, 2022 at 01:35:41PM +0300, Ilpo Järvinen wrote:
> > Not all LSR register flags are preserved across reads. Therefore, LSR
> > readers must store the non-preserved bits into lsr_save_flags.
> >
> > This fix was initially mixed into feature commit f6f586102add ("serial:
> > 8250: Handle UART without interrupt on TEMT using em485"). However,
> > that feature change had a flaw and it was reverted to make room for
> > simpler approach providing the same feature. The embedded fix got
> > reverted with the feature change.
> >
> > Re-add the lsr_save_flags fix and properly mark it's a fix.
> >
> > Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
> > Link: https://lore.kernel.org/all/1d6c31d-d194-9e6a-ddf9-5f29af829f3@xxxxxxxxxxxxxxx/T/#m1737eef986bd20cf19593e344cebd7b0244945fc
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> >
> > ---
> > Since Uwe didn't follow up with this fix in an isolated patch, I'm sending
> > it now so that it doesn't end up falling through cracks.
>
> Great, thanks. I completely obliterate that one.
>
> Maybe it would be sensible to wrap reading + updating saved_flags in an
> inline helper?
It's my plan. I just wanted to get the obvious fix out of the way first.
> Other than that:
>
> Acked-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
>
> > tg: (4419da5d5d4b..) fix/lsr-save-flags (depends on: tty-next)
>
> Oh wow, you're using topgit? I would be interested in your pain points
> and what made you choose topgit anyhow. Since a longer time I have a few
> ideas for a git helper that uses the good ideas in topgit, but never
> came around to implement it.
Yes, I am. The most problematic case is when I'd want to reorder/relocate
a patch towards root. I usually end up just creating another one with a
different name. I've learned to cope most of what I'd assume many people
would find pain points with manual tg patch | patch -p1 -R trickery
(possibly combined with git add -i) and reapplying afterwards, it gets me
quite far already.
--
i.
