serial: 8250: Adjust misleading LSR related comment

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serial8250_rx_chars() has max_count based character limit. If it
triggers, the function returns the old LSR value (and it has never
returned only flags which were not handled). Adjust the comment to
match behavior and warn about which flags can be depended on.

I'd have moved LSR read before LSR read and used serial_lsr_in() also
here but I came across an old discussion about the topic. That
discussion generated commit d22f8f1068 ("serial: 8250: Fix lost rx
state") so I left the code as it is (it works as long as the callers
only use a subset of the LSR flags which holds true today) and changed
the comment instead.

Link: https://www.spinics.net/lists/linux-serial/msg16220.html
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220608095431.18376-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Ilpo Järvinen 2022-06-08 12:54:29 +03:00 • committed by Greg Kroah-Hartman

parent 6a4241e8f9

commit 7a3525e48c

1 changed files with 5 additions and 3 deletions

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drivers/tty/serial/8250/8250_port.c

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