Re: Include request for reset-rework branch v3

["Christian König" <deathsimple@vodafone.de>]

On 02.05.2012 12:32, Dave Airlie wrote:
> On Wed, May 2, 2012 at 10:04 AM, Christian König
> <deathsimple@vodafone.de>  wrote:
>> On 02.05.2012 06:04, Jerome Glisse wrote:
>>> On Wed, May 2, 2012 at 12:00 AM,<j.glisse@gmail.com>    wrote:
>>>> Ok so i reread stuff and the :
>>>> drm/radeon: add general purpose fence signaled callback
>>>> is a big NAK actually. It change the paradigm. Moving most of
>>>> the handling into the irq process which is something i am intimatly
>>>> convinced we should avoid.
>>>>
>>>> Here is the patchset up to ib pool cleanup. I have yet rebase the
>>>> other patches as i am tracking done some issue in the sa allocation.
>>>>
>>>> Cheers,
>>>> Jerome
>>>>
>>> Before i forget, the big issue with doing work from irq handler is that
>>> we never know in middle of what other part can be. I believe it's lot
>>> better to have irq process only update fence (signaled/not signaled).
>>> and have the actual work happening on behalf of the process wether
>>> through sa alloc path or ttm path.
>>
>> Disagree.
>>
>> Why should it be better to delay work outside of the interrupt context if
>> proper locking can make the driver much more responsive and easier to
>> implement?
>>
>> I don't want to call into TTM or stuff like that, just want make it possible
>> to release the resources acquired for a job immediately after the job is
>> completed instead of waiting for the next allocation to happen. Cause then
>> you don't need to check if a bunch of fences might possible be signaled and
>> instead just get a proper signal that resources can be deallocated.
>>
>> Also if you really want to keep the irq context out of the drivers upper
>> layers, it should be quite easy to modify the code so that the callback
>> won't happen from there.
> as a general rule try an minimise how much work we do in irq context,
> the locking gets very messy once you have to use a mutex somewhere
> else in the future.
Akk, that sounds reasonable, but I still think that a fence should 
signal it's completion by itself. Because that releases us from the 
burden to walk the list of emitted fences and heuristically check if any 
of them is already signaled.

Also it is pretty easy to move the callback outside of interrupt 
context, but first things first.  I'm going to write together a patchset 
with everything that is already accepted, so we can stop mailing around 
actually unrelated patches.

Thanks for the comments,
Christian.