Re: [PATCH] Exar quad port serial

[Paul B Schroeder <pschroeder@uplogix.com>]

Lennart Sorensen wrote:
> 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.
> 
Yea..  I tried that..  It had no effect..

> 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).
In that case, I will redo the patch with better labeling..

Thanks...Paul...



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Paul B Schroeder <pschroeder "at" uplogix "dot" com>
Senior Software Engineer
Uplogix, Inc. (http://www.uplogix.com/)