On Fri, 2007-07-27 at 13:48 -0700, Lee Howard wrote: > Here's the output: > > type: 4 > line: 1 > line: 760 > irq: 3 > flags: 1358954688 > xmit_fifo_size: 16 > custom_divisor: 0 > baud_base: 115200
OK, the FIFO should be enabled. What is known: * The error is a hardware FIFO overrun. - observed message is in n_tty due to driver setting TTY_OVERRUN * The RTS/CTS flow control is not involved - this is done only by the ldisc in response to buffer levels - you verified crtscts is set - you did not observed RTS change when 'overflow error' logged - you did observe RTS change when application stopped reading So this seems to be a latency issue reading the receive FIFO in the ISR. The current rx FIFO trigger level should be 8 bytes (UART_FCR_R_TRIG_10) which gives the ISR 694usec to get the data at 115200bps. IIRC, in 2.2.X kernels this defaulted to 4 bytes (TRIG_01) which gave a little more time to service the interrupt. How does the data rate affect the frequency of the overrun errors? Does 57600bps make them go away? -- Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
