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    SubjectRe: [PATCH] tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done
    On Mon, Jan 02, 2017 at 03:14:37PM +0100, Richard Genoud wrote:
    > 2017-01-02 12:53 GMT+01:00 Alexandre Belloni
    > <alexandre.belloni@free-electrons.com>:
    > > On 06/12/2016 at 13:05:33 +0100, Richard Genoud wrote :
    > >> When using RS485 in half duplex, RX should be enabled when TX is
    > >> finished, and stopped when TX starts.
    > >>
    > >> Before commit 0058f0871efe7b01c6 ("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 0058f0871efe7b01c6
    > >> ("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.
    > >>
    > >> Cc: stable@vger.kernel.org
    > >> Reported-by: Gil Weber <webergil@gmail.com>
    > >> 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>
    > >
    > Greg, could you take this patch in your tree ?

    Yes, will do so, thanks.

    greg k-h

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