On Mon, Jan 22, 2018 at 3:34 PM, Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > Hi, > > On Sat, Jan 20, 2018 at 11:37:28AM +0800, Chen-Yu Tsai wrote: >> On Fri, Jan 19, 2018 at 9:32 PM, Maxime Ripard >> <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: >> > The DRM driver most notably, but also out of tree drivers (for now) like >> > the VPU or GPU drivers, are quite big consumers of large, contiguous memory >> > buffers. However, the sunxi_defconfig doesn't enable CMA in order to >> > mitigate that, which makes them almost unusable. >> > >> > Enable it to make sure it somewhat works. >> >> IIRC the default size for CMA pretty much limits it to small tablet >> screen resolutions. Is this something we want to leave up to the >> user? > > That's one of the pain points of CMA in our case. The amount of memory > you need depends on the resolution itself, but also the number of > multiple buffers you want to use, and even the number of planes you > want to use. > > And then, you have to trade that off with the amount of RAM you have > on your board in order to still have something that's usable. > > tl;dr: I don't really see how to define a value good enough for > everyone. Yeah, that's what I thought. On the other hand, I don't think any of the kernelci boards have display enabled? So either way we won't see any automated tests fail. ChenYu