* Peter Hurley | 2014-09-23 13:03:51 [-0400]: >readline() does this; it 'saves' the caller's termios, sets termios >for non-canonical reads, reads one char, and 'restores' the caller's >termios. interresting, thanks. I guess I would need to opimize this a little so the baudrate isn't going to 0 and back to the requested baudrate. >The tty core calls the driver's wait_until_sent() method before changing >the termios (if TCSADRAIN is used for tcsetattr(), which I think for readline() >it does). The interresting difference is that when I take the yocto RFS and chroot into from Debian then I don't this problem. Not sure if this is really readline or something else… >But DMA is cheating if the UART driver's tx_empty() method is saying the >transmitter is empty while TX DMA is still running. This shouldn't be the case. But I will check this once I able to. After TX-DMA is done, "xmit->tail" is updated and port.icount.tx is incremented. At this time the TX FIFO is still full (up to 64 bytes) and I set UART_IER_THRI to wait until TX FIFO is empty so I can disable runtime-pm. Therefore I would assume LSR does not say BOTH_EMPTY until the FIFO is empty. >Regards, >Peter Hurley Sebastian -- 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
