Messages in this thread | | | Date | Wed, 11 Jan 2017 08:09:09 +0100 | From | Greg KH <> | Subject | Re: [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
| |