Matthias Drochner <drochner@zelux6.zel.kfa-juelich.de> writes:

> > Note that this patch doesn't include the patch to use the card over
> > 115200 bps, since it is separate function.
> 
> Did you know that there is Linux driver source available
> which uses enhanced features? (via www.hayes.com)

I didn't look the driver, but I got a document from anonymous ftp
server of hayes.com.  I wrote above notice so that someone won't
expect the feature which I implemented in my old PR.

> I don't know the ESP cards, and I don't know if this would
> give us more performance, however.

I think ESP cards have four major enhanced feature; (1) 1024 byte
fifo, (2) over 115200 bps rate, (3) memory mapped io and (4) DMA.
Even in ns16550 compatile mode, (1) is already achieved with current
com driver and (2) is probably available with my diff in old PR (I got
one report that it doesn't work, but I can't debug it yet).  To
achieve (3) and/or (4), the card should be operated in enhanced mode
and probably new driver needs, but I don't know how much does it
desired.  I'm currently using a ESP card on 486DX2/66 box to connect
my ISP via 128kbps ISDN TA at 230400bps, and at least with this rate,
it seems works well enough.

> Regarding your PR kern/4095: When I cleaned up the
> serial console stuff some weeks ago, I came to the same
> conclusion. I asked for testers at the mailing list too, but
> there was nobody who could do it without too much effort.
> Perhaps we should simply integrate it?

Yes, since, as I wrote in my PR, I believe it is a bug as far as
reading the source.  Could one or two more person review the logic?

enami.