On 12/03/2015 12:29 PM, Matwey V. Kornilov wrote: > 2015-12-03 17:41 GMT+03:00 Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>: >> Hi Matwey, >> >> On 12/03/2015 12:50 AM, Matwey V. Kornilov wrote: >>> I am working on v4, where I completely redesigned implementation. And >>> now I think that it is considerably better than v3. >>> It looks like the following: >>> https://github.com/matwey/linux/commits/8520_rs485_v4 >>> But it is not ready yet, there is a bug somewhere. >>> >>> In the v4, each subdriver decides separately if it needs rs485 >>> emulation support. Then it enables it like the following: >>> https://github.com/matwey/linux/commit/4455e425fc045713fb921ccec695fe183f1558f0 >>> Before calling serial8250_rs485_emul_enabled, the driver enables >>> interrupt on empty shift register (they are always there for omap_). >> >> Looks good. >> >> Are you testing with CONFIG_SERIAL_8250_DMA=n first to simplify the >> debug effort? DMA adds a completely different tx path. > > Many thanks for the advice. I've just found that the bug is not in my code =) > Even with pure 4.3.0 I cannot open /dev/ttyS5 more than once. It just > hangs on open() and the process is in S+ state. Hmm, that's odd. So $ stty -a < /dev/ttyS5 hangs if something like below is running? $ cat > /dev/ttyS5 >> Also, before submission, please shorten the identifiers. And Greg hates >> functions returning bool so just expanded serial8250_rs485_emul_enabled() >> inline. > > Am I allowed to use `re' instead of rs485_emul in names? Long names and constructs tend to obscure the execution flow. Some of the names could be reduced where the meaning is obvious: serial8250_rts_on_send serial8250_rts_after_send serial8250_handle_start_timer serial8250_handle_stop_timer These two I would inline into their lone call site: serial8250_rs485_emul_startup() serial8250_rs485_emul_shutdown() serial8250_rs485_emul_start_tx => __start_tx_rs485 rs485_emul => sw485/em485/emul485/soft485 ? Or just rs485 (except for the field name and structs so as not to confuse it with the port->rs485) Just my 2¢ Regards, Peter Hurley -- 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
