RE: Output character lost with 8250 UART driver

["Chris Doré" <cdore@connecttech.com>]

> -----Original Message-----
> From: ZhangXiao
> Sent: June 25, 2008 4:07 AM
> 
> Based on theses lines, characters should be written to the THR
> continuous, no matter if it had already move the character to the TSR. I
> think it is not safe in some cases so I add a line
> 
> 	wait_for_xmitr(up, UART_LSR_THRE);
> 
> before line 3. And then the issue in my target was disappeared. This is
> a static function that was already exist in the same file. It just check
> and wait until the THR was empty.

Do you have the FIFO's disabled, but transmit_chars() thinks they are
enabled?
Sounds to me like that might be your problem and without the
wait_for_xmitr() call you are overrunning the transmitter.  In other words,
if you have FIFOs disabled, up->tx_loadsz should be 1.

What UART are you using?


..Chris