On Oct 19, 2016 2:33 PM, "Nicolai Hähnle" nhaehnle@gmail.com wrote:
On 19.10.2016 01:40, Marek Olšák wrote:
- We can build upon this idea. I think the worst thing to do would
be to add metadata handling to driver-agnostic userspace APIs. Really, driver-agnostic APIs shouldn't know about that, because they can't understand all the hw-specific information encoded in the metadata. Also, when you want to change the metadata format, you only have to update the affected drivers, not userspace APIs.
I don't fully agree with that. In a PRIME setting, where you have a
compositor running on an integrated GPU and an application on a dGPU, there may well be a benefit to finding a tiling format that the dGPU can produce and the iGPU can consume. Admittedly I don't know whether that's actually possible today when they're from different vendors, but resigning ourselves to linear only for all time seems a bit pessimistic.
Yeah, that's a good point and I even mentioned it near the end of my post. It could be solved by passing the PCI ID of the other device to the driver instead of the linear flag. Then the driver can decide whether a linear layout is necessary or not.
Marek