Hi,

I have a console driver that registers an additional boot console and
"normal" console. The command line is:
earlycon=uart8250,mmio32,0x68A10000 console=ttyS0,115200n8
earlylog=0x8f110000,0x10000

When the second bootconsole is registered via register_console(), the
output in the log buffer is written a second time to the uart8250
console resulting in duplicate output. When the second "normal"
console is registered the complete buffer is written again to
uart8250. It looks like a bug in printk but I'm still trying to figure
out how it's keeping track of what has been written to a console.

I've attached the driver and uart8250 output.

Thanks.