Using integrated Radeon 7560D with 2GB of VRAM?

[gradinaruvasile]

My question is if i allocate 2 GB of VRAM to the IGP, will it be able to use all of it by default (no kernel module parameters).
I have this in the dmesg:

[    7.037449] [drm] radeon: 2048M of VRAM memory ready
[    7.037452] [drm] radeon: 1024M of GTT memory ready.

Does this mean that the GPU can access up to 1024 MB of system RAM or it can access the 2048 VRAM and additional 1024 RAM?

[bridgman]

Does this mean that the GPU can access up to 1024 MB of system RAM or it can access the 2048 VRAM and additional 1024 RAM?

The latter AFAIK. The 2048 MB of "VRAM" is permanently carved out from system memory at boot time and not visible to the OS memory manager, while the 1024 MB of "GART" is backed by OS-managed pages as needed.

My understanding (thanks to agd5f) is that the 1024M message really means "enough page tables have been created to cover 1024M of pages", which sets an upper limit on the amount of system memory that can be used for "GART" via subsequent buffer operations.

[gradinaruvasile]

Ok thanks. top shows that i have ~10GB available of the 12 total, but i was wondering if all of that can actually be used.

[curaga]

Partial hijack - are GTT pages freed again after the process exits?

I ask because after running a 3d app, there's about 500mb of RAM that doesn't come back even after quitting X.