The character transmission in xuartps is racy. If the transmitter is disabled
early, the device is confused and produces a desync. Garbage on the remote end
can be a visible symptom. The second patch in this series tries to reduce that
race condition in accordance with the hardware documentation, but it cannot
remove it entirely. The first and third patches are code cleanup.
Changes since v2:
* Do not attempt to disable the transmitter after a transmission (original
behaviour around 3.14). These patches no longer touch with the transmitter
state at all as requested by Sören Brinkmann.
* Add Acked-by/Reviewed-by tags from Sören Brinkmann after addressing his
remarks.
Earlier patches/discussion at:
https://www.spinics.net/lists/linux-serial/msg23145.html
https://www.spinics.net/lists/linux-serial/msg23156.html
https://www.spinics.net/lists/linux-serial/msg23157.html
Helmut Grohne (3):
serial: xuartps: fix typo in cdns_uart_startup
serial: xuartps: reduce hardware TX race condition
serial: xuartps: remove unnecessary register write
drivers/tty/serial/xilinx_uartps.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)
--
2.11.0
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