On 09/10/2014 09:52 PM, Peter Hurley wrote: > The serial core can't assume that start_tx() does not need invoking > because hardware that can stop_tx() with data in the transmitter > won't restart if the ring buffer is empty but data is still in the > transmitter. [Note that the 16C950 port type does this in the 8250 driver.] oh, not sure how I missed this… But now that I look at this, it is also that ->x_char that could be use for flow control which would have to be sent even with an empty xmit buffer. And 8250 in DMA mode does not look at x_char at all. But it would be better if it would, right? However if the TX side does a 2 KiB transfer not sure what should be done… > So this has to be handled in the 8250 driver. > > What is the actual issue? Are you trying not to unnecessarily wake > the omap hardware if runtime-PM is on? no, it is actually the extra interrupt for no reason that looked like not needed at all. But I guess it is only during "startup" while the init-script do fancy things and not during "normal" operations. > 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
