i386/105616: UART PCI device just silent...

[Helge Oldach]

The following reply was made to PR i386/105616; it has been noted by GNATS.

From: puc-uart at oldach.net (Helge Oldach)
To: xcllnt at mac.com (Marcel Moolenaar)
Cc: FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: i386/105616: UART PCI device just silent...
Date: Tue, 28 Nov 2006 21:14:19 +0100 (CET)

 Hi Marcel,
 
 >> The only thing that may be botched is speed, or potentially also
 >> parity or stop bits.
 >It's definitely an odd failure mode. What happens if you wire one of
 >the UART ports on the PCI card to one of the "legacy" on-board serial
 >ports? Could you try both the PCI UARTs?
 
 I did. What happens is that single, typed-in characters don't make
 to the remote, while files piped to the remote via ~>file appear as
 garbage. The garbage contains a lot of 0xff characters. So there *is*
 some sort of communication in place. It doesn't matter whether I send
 on the puc uart or the on-board uart. It also doesn't make too much
 difference if I play with the transmit and receive speeds.
 
 This all points into the direction of speed (parity, stopbits) mismatch.
 
 Going to extremes: When I set the puc UART to 1200 bps and the on-board
 to 115200, I constantly receive a 0xff on the on-board for any arbitrary
 character typed on the puc uart. But there is silence the other way
 'round.
 
 There is no difference between the two puc/uart ports. Garbage either
 way, but at least there is communication on both ports. So IO ports and
 IRQ are likely correct.
 
 Any further ideas? Is there a simple means to measure the actual speed?
 
 Helge