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? 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. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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