Re: [Dri-devel] Re: DRM and pci_driver conversion

[Philip Brown <phil@bolthole.com>]

On Mon, Oct 27, 2003 at 06:13:32PM -0800, Linus Torvalds wrote:
>..
> So the thing should really just have 
>  - discovery and attach/detach
>  - interrupt event notification (and it can't just be "an interrupt 
>    happened" - the interrupt driver actually has to know enough to ACK the
>    interrupt, so that we can tell user space that an interrupt happened 
>    without having to disable the interrupt until the event goes away)
>  - serialization (ie a lock) and waiting for events ("engine idle" or 
>    "command queue less than half full")
>  - DMA arbitration and setup.
>[....]
> So the low-level driver wouldn't know about palettes or cursors or any 
> "high-level" concepts like that. It would have a few locks to make sure 
> that the users that try to access the things don't stop on each other, 
> nothing more (maybe the locks themselves would be grouped into "palette 
> lock" vs "cursor lock" vs "DMA engine lock" since hardware may be threaded 
> enough to allow it, but the point is that the low-level driver wouldn't 
> actually _do_ anything, it only allows others to do what they want without 
> stomping on each others toes).

Sounds like a good idea. Simple Is Better.

Now, would that "DMA arbitration" include
"submit a chunk o dma memory for GPU processing",

or would it just allow [whatever] to map the registers, and basically say,
"I'll tell you when something completes (aka sends an interrupt)
 but it's up to you to START it"





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