Issue in printing to console using interrupts.

Andrei Chichak groups at
Wed Feb 23 23:21:35 UTC 2011

Is it possible that there are two tasks using the UART? 

One would write a bunch of stuff out, be scheduled out, the next takes over, stuffs stuff into the send queue, the first gets scheduled in, continues. Messages get intermixed.

To get it straightened out, put a semaphore around all of your printk calls.

My naive offer. I'm sure the Gods on the list have much better opinions.


On 2011-February-23, at 3:50 PM, Rohan Kangralkar wrote:

> Hi all,
> I have a console uart on a blackfin processor.
> The driver prints fine when the UART is in polling mode. But when the UART uses interrupts to send characters then it messes up the output. It mixes the characters from different tasks .
> The log for the ticker test is given below.

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