Hans Verkuil wrote:
> On Wednesday 20 December 2006 07:45, Steven Ellis wrote:
>   
>> Hans Verkuil wrote:
>>     
>>> Hi all,
>>>
>>> I think it is getting time for people to start testing the ivtv
>>> trunk from subversion. I've been running it for quite some time now
>>> and it looks to be pretty solid. Ian Armstrong has added lots of
>>> goodies in the framebuffer department (be sure to read the README
>>> notes!), so that can use some testing as well.
>>>
>>> Regarding DMA problems: I think that these are solved for the
>>> PVR500. I haven't yet done a REALLY long duration test but from the
>>> shorter tests I did it is looking good. The DMA errors still occur
>>> for other cards: it is a hardware issue with the cx23415/6 and
>>> there probably isn't anything I can do about it. Just don't use CPU
>>> freq. changers and sometimes using a RAID array also messes up the
>>> DMA.
>>>
>>> The reason that it works for the PVR500 is that the PVR500 has a
>>> PCI bridge that seems to isolate the cx23416 chips from the main
>>> PCI bus. It still could fail on the 0.9 drivers due to the way DMA
>>> was handled in the driver. With the new trunk driver all DMA is now
>>> done in the interrupt handler.
>>>
>>> Note: ivtv trunk requires the 2.6.19 kernel. It is probably very
>>> easy to backport it to 2.6.18, it may even compile out of the box.
>>> I just haven't tested it myself. When this driver version is
>>> released I'll definitely backport it to 2.6.18.
>>>
>>> The trunk driver can be obtained here:
>>>
>>> http://ivtvdriver.org/viewcvs/ivtv/trunk.tar.gz?view=tar
>>>       
>> Great work Hans. Shame I don't have a machine with a 2.6.19 kernel
>> running.
>>
>> How much of this might be backportable to the 0.4.x branch? Testing
>> 0.4.9 at present at it seems to work well on my setup, but I'd like
>> to reduce the DMA issues further.
>>     
>
> All I can say is that I'm not going to backport this to 0.4.x. I have to 
> make choices where I spend my time, and backporting simply takes too 
> much time. It's not a trivial thing to do. But if someone else would be 
> willing to take this on, then I'm happy to help out.
>   
Given the benefits I might be willing to work on it. At the moment I'd
love to move all of the myPVR customers to a 2.6.18 kernel but there is
a lot of regression testing required. Might have some time between
Christmas and New Year to attempt it if you give me some pointers.

Steve

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