Re: [PATCH v8 1/9] serial: max310x: don't clobber the TX break bit in set_termios

[sashiko-bot@kernel.org]

> A TX break asserted with TIOCSBRK ends early, with no error reported,
> as soon as any termios change lands on the port: a break is a state
> that must hold until TIOCCBRK, but max310x_set_termios() overwrites
> the whole LCR register, and LCR also carries the TX break bit that
> break_ctl() drives. No concurrency is required - a baud or parity
> change from the same process ends the break just as well, and
> break-led protocols lose their break with nothing in the logs.
> 
> Update only the LCR bits that are derived from termios and leave the
> TX break and RTS pin control bits untouched. Since nothing clears a
> break when a port is closed with the break still asserted - the tty
> core sends no break-off on release, and the unconditional write here
> was the accidental recovery - clear TXBREAK in startup(), the same way
> 8250 does.
> 
> Fixes: f65444187a66 ("serial: New serial driver MAX310X")
> Assisted-by: Claude:claude-fable-5
> Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261008-max310x-rs485-sw-delay-v8-0-6ba881f81e1f@vaisala.com?part=1