linux-kernel - Re: Stupid user with user-space questions, matrix LED driving with user space code only.

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Date:	Mon, 18 Feb 2013 11:55:38 +0000 (UTC)
From:	el es <el.es.cr@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: Stupid user with user-space questions, matrix LED driving with user space code only.

Jonathan Andrews <jon <at> jonshouse.co.uk> writes:


> 
> What about a yield alignment mechanism for user space. IE the process
> calls the kernel with a request "schedule me first after a yeild" - then
> the process at least has whatever the timer granularity is to do
> something timing critical... add a flag to ignore or defer interrupts
> and you have a semi 'hard-realtime' behaviour for user space, allowing
> user space to grab small chunks of real time. Yes a nasty looking
> facility for SMP intel servers but really useful for embedded.
> 

Seems you have some (bad?) habits from embedded programming, 
you think Linux is FreeRTOS ;)

Linux as such, as far as I read, is not a real-time OS, it will 
NOT do what you want in userspace, (maybe unless you build it with
the RT patchset?)

Better take the advice and go build a kernel driver for this display.

Or use a small microcontroller that won't have the limitations. 

> Thanks,
> Jon
> 
> 
Lukasz



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