Dear Ezequiel Garcia,

On Wed, 27 Nov 2013 15:54:49 -0300, Ezequiel Garcia wrote:

quoted

An external device may be keeping the UART busy and preventing LCR
from being written.

What device is attached to ttyS1?

There's no device attached at ttyS1. I've just tested this in another
box and it seems the same error is obtained on each unused port:

Are you sure about this? I suppose you're testing on the Armada XP GP
board, and this board has a 4 ports FTDI chip, and according to the
board schematics the four UARTs are all connected to the FTDI chip. So
from the SoC perspective, ttyS1 is connected to something, as far as I
can understand. Or maybe you also tested Armada XP DB ?

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com