Re: Printf hangs when internal buffer of driver is temporarily full

[Philip Oberstaller <Philip.Oberstaller@septentrio.com>]

On 01/14/2013 08:36 PM, Alan Cox wrote:
>> which happens when the driver's internal buffer is temporarily full.
>> I would have expected that the TTY layer or the libc implementation of
>> printf would requery write_room automatically and thus would notice
>
> How is it going to magically notice ?
>
>> after a while that there is space again, but this doesn't seem to happen.
>> Eventually the printf function returns after a very long timeout but without
>> that the remaining characters have been printed.
>
> You need to wake it up and tell it there is room in your completion
> interrupts. It will then think about retrying.

Yeah, behind the magic there is most of the time some manual work. Thanks
for the hint of the wakeup! That definitely makes it working. Don't ask
me why I didn't see it before...

> I would suggest recycling that book 8)

Agreed, but as it's pretty cold these days, it might well be used for
some other purpose...

(Sorry for the disclaimer, but it cannot be circumvented when sending
from this domain - at least I would not know how)

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