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List:       linux-kernel
Subject:    Re: Bug in 8520.c - port.type not set for serial console
From:       Bjorn Helgaas <bjorn.helgaas () hp ! com>
Date:       2005-05-31 22:25:46
Message-ID: 200505311625.46084.bjorn.helgaas () hp ! com
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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.
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