[ECOS] RE: Reentrancy of the ecos drivers

Gary Thomas gary@mlbassoc.com
Tue Jul 18 12:26:00 GMT 2006


harbonne marc wrote:
> 
> 
> Hi all,
> 
>  
> 
> My question is quite general, I cannot see in any ecos drivers provided with
> the last version of ecos, a way to protect the shared resources.
> 
>  
> 
> As example, if you look at any display driver, we cannot see a semaphore
> that will protect from a second task to access to the resource by
> pre-empting the one which has the resource.
> 
>  
> 
> The only call I can see is a cyg_scheduler_lock and unlock to get/release
> the resource.
> 
>  
> 
> But in many drivers such mechanism does not exist.
> 
> Can you tell me why?

In most cases, such resource management (if it's required) is handled
at a level higher than the physical device driver.

What driver(s) are you concerned about?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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