Re: Bug in 8520.c - port.type not set for serial console

Bjorn Helgaas
2005-05-31T22:27:16Z

On Monday 30 May 2005 4:38 pm, Jim Ramsay wrote:
> I am attempting to get the 8520.c driver's serial console working with
> a 16550A UART implementation, and have run into what I consider to be
> a bug: In short, the proper 'port.type' for this serial port is not
> set until the module init (serial8250_init) is called, so the FCR is
> set incorrectly during serial8250_console_init for any port type which
> is different than UNKNOWN.
>
> The exact problem is that the FCR is being set to '0x0' for a port
> type of 'UNKNOWN', when for my specific 16550A, it should be set to
> '0xC1' - and this makes my screen fill with empty characters instead
> of the printk output I need.

Shouldn't a 16550A UART work correctly with FCR==0x0, i.e., with FIFOs
disabled? Is your UART broken?

Serial console output is always polled, one character at a time, so
you shouldn't need FIFOs until later.