Re: [PATCH v4 01/19] drm: Add |struct drm_gem_vram_object| and helpers

Hi,

This misses the call to drm_gem_vram_placement(), where drm_gem_vram_push_to_system() enforces placement in system memory.

Ah, missed that detail.

We could build a common implementation out of both interfaces, but that would obfuscate the code IMHO. I'd just leave it as it is.

Ok.

...

...

+struct drm_gem_vram_object {

• /* Supported placements are %TTM_PL_VRAM and %TTM_PL_SYSTEM */
• struct ttm_placement placement;
• struct ttm_place placements[3];

placements[2] should be enough I guess?

TTM_PL_VRAM has index 2 and TTM_PL_SYSTEM has index 0. There's TTM_PL_TT at index 1. We don't use all three array entries here, but I'm not sure if something in TTM does. I took the line from the drivers and didn't change it for that reason.

TTM_PL_* isn't an index into that array. See drm_gem_vram_placement() which fills that array. It'll use one or two entries of that array.

cheers, Gerd