Hi Clemens, On Sat, Jan 7, 2017 at 9:06 PM, Clemens Gruber <clemens.gruber@xxxxxxxxxxxx> wrote: > Just remuxed GPIO signals to these pads, applied your two patches and > used rts-gpios in the DT but I still see the same problem :/ > > When transmit something, I get doubled characters, then zeros and at the > end garbled data of previous transmissions, same as described in my > first post (Logic analyzer: https://pqgruber.com/rs485_results.png) > The data is always 4096 bytes long, this explains why the echo command > is blocking for about 4 seconds (<- 4096 bytes at a baudrate of 9600). > The TE line is also high until all 4096 bytes are sent. > > I think this comes from the UART_XMIT_SIZE which is defined to the page > size. > Maybe there is something wrong in imx_transmit_buffer and leads to the > whole circular buffer being sent out all the time, not stopping.. > > Do these debug logs tell you anything? > https://gist.github.com/clemensg/1ac5ee8a8ea32acc9145c5aa8407aea5 > > I am analyzing the signals coming directly from the i.MX6Q, so this must > be a software problem, but I don't understand why it works for you, if > we use the same software. > > Do you use any other patches on top of mainline and do you use the SDMA > scripts from the ROM? No, I use the original 4.9 + the two patches I sent. Yes, I do use the SDMA scripts from ROM. Here is the procedure I did to try to reproduce the issue you reported: (The rs485conf is available at: https://github.com/mniestroj/rs485conf/blob/master/main.c ) First of all I enable rs485 for ttymxc3 using the rs485conf application: root@imx6qsabresd:/home# ./rs485conf /dev/ttymxc3 -e 1 [ 27.106517] random: crng init done = Current configuration: RS485 enabled: false RTS on send: high RTS after send: low RTS delay before send: 0 RTS delay after send: 0 Receive during sending data: true = New configuration: RS485 enabled: true RTS on send: high RTS after send: low RTS delay before send: 0 RTS delay after send: 0 Receive during sending data: true = Saved configuration: RS485 enabled: true RTS on send: high RTS after send: low RTS delay before send: 0 RTS delay after send: 0 Receive during sending data: true root@imx6qsabresd:/ho Then root@imx6qsabresd:/home# echo A > /dev/ttymxc3 (wait 10 seconds) root@imx6qsabresd:/home# echo B > /dev/ttymxc3 (wait 10 seconds) root@imx6qsabresd:/home# echo C > /dev/ttymxc3 On the serial console at 9600bps only the: A B C are seen, so not duplicated characters, nor noise is seen on the console. Regards, Fabio Estevam -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
