Re: I/O operations priority in RTOS

[Armin Steinhoff <armin@steinhoff.de>]

Nicholas Mc Guire wrote:
> On Sun, 05 Jun 2011, Armin Steinhoff wrote:
>
>> Nicholas Mc Guire wrote:
>>> On Sat, 04 Jun 2011, Monica Puig-Pey wrote:
>>>
>>>> Hello,
>>>> I'm studying how to develop drivers in a real time OS and how do they
>>>> work. I'm using  Ubuntu 10.04 with the 2.6.31-11-rt patch installed.
>>>> I would like to know the priority when executing open(), read(), write()
>>>> and close() operations.
>>>> In my example the thread which is using the driver runs with 10 RTPRIO,
>>>> but I don't know what happens in kernel context with the priority when
>>>> running the I/O operations.
>>>> Thank you for your help, I don't know where to learn about this.
>>>>
>>> []
>>> Also when using bottom half mechanisms you need to take into account the
>>> priority of the kernel thread that manages the defered work items, so
>>> rt-drivers may have a different structure than normal drivers.
>> That's the reason why I prefer UIO based user space drivers !
>>
> ...and how to resolve DMA ? if DMA were resolved cleanly I would agree.

https://opensource.qualcomm.com/wiki/UIO-DMA

I haven't tested until now  ... what do you think about it ?

--Armin


> hofrat
>