commit b389f173aa upstream.
When using RS485 in half duplex, RX should be enabled when TX is
finished, and stopped when TX starts.
Before commit 0058f0871e ("tty/serial: atmel: fix RS485 half
duplex with DMA"), RX was not disabled in atmel_start_tx() if the DMA
was used. So, collisions could happened.
But disabling RX in atmel_start_tx() uncovered another bug:
RX was enabled again in the wrong place (in atmel_tx_dma) instead of
being enabled when TX is finished (in atmel_complete_tx_dma), so the
transmission simply stopped.
This bug was not triggered before commit 0058f0871e
("tty/serial: atmel: fix RS485 half duplex with DMA") because RX was
never disabled before.
Moving atmel_start_rx() in atmel_complete_tx_dma() corrects the problem.
Reported-by: Gil Weber <webergil@gmail.com>
Fixes: 0058f0871e
Tested-by: Gil Weber <webergil@gmail.com>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: Bryan Evenson <bevenson@melinkcorp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
990a142ee0