* Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> [140815 12:16]: > On 08/15/2014 08:17 PM, Lennart Sorensen wrote: > > > Are you saying that with the new driver you have to respond to the RX > > irq faster than before to avoid overflows? It is not quite clear. > > Yes. The irq fires 46 bytes giving you 16 bytes buffer before overflow > vs 63 bytes buffer the old one had. > > > I do think 40000 interrupts to handle 40000 bytes of date does seem a > > tad inefficient, so dropping to 854 looks a lot nicer. Was the omap > > driver not using the fifo trigger levels at all? > > It configured the trigger levels to 1 for RX and 16 for TX. Hmm that weird RX trigger level is a workaround for lost characters. See commit 0ba5f66836 (tty: serial: OMAP: use a 1-byte RX FIFO threshold in PIO mode :) There's paste test in that commit, I wonder if the 8250 drivers can deal with it any better? Regards, Tony -- 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
