Re: [PATCH] Exar quad port serial

On Tue, Oct 17, 2006 at 08:00:17PM -0500, Paul B Schroeder wrote:
Sorry for the late response.. Here is a fuller explanation. Maybe
somebody out there has a better solution:

This is on our "Envoy" boxes which we have, according to the documentation,
an "Exar ST16C554/554D Quad UART with 16-byte Fifo's". The box also has
two other "on-board" serial ports and a modem chip.

The two on-board serial UARTs were being detected along with the first two
Exar UARTs. The last two Exar UARTs were not showing up and neither was
the modem.

This patch was the only way I could the kernel to see beyond the standard
four serial ports and get all four of the Exar UARTs to show up.

I hope this explains it well enough..

I suspect all you have to do might be to change how many ports it looks
for. The default max ports is 4 I believe on many kernel versions.

Look for CONFIG_SERIAL_8250_NR_UARTS and
CONFIG_SERIAL_8250_RUNTIME_UARTS in the kernel config.

If that doesn't work and you do need a special driver, at least label it
with more detail like 'for exar st16c554 quad uart' or 'for envoy board'
or whatever makes it clear which hardware it is for. I use exar pci
uarts (exar XR17d15[248] chips) which work fine already with the 8250
driver, or optionally with the jsm driver with a small change to the
list if pci identifiers. THey of course would not work with your driver
since they are completely different exar chips (even though one is also
a quad uart, although 64byte fifo).

--
Len Sorensen
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