If we ever want to be able to use the 3D engine we have no choice. It
appears that the tiling setup (required for 3D on G8x) is in the page tables.
The immediate benefit of this change however is that it's now not possible
for a client to use the GPU to render over the top of important engine setup
tables, which also live in VRAM.
G8x VRAM size is limited to 512MiB at the moment, as we use a 1-1 mapping
of real vram pages to their offset within the start of a channel's VRAM
DMA object and only populate a single PDE for VRAM use.
As a fallout, replace filp storage with file_priv storage for "unique
identifier of a client" all over the DRM. There is a 1:1 mapping, so this
should be a noop. This could be a minor performance improvement, as everything
on Linux dereferenced filp to get file_priv anyway, while only the mmap ioctls
went the other direction.
This was used to make all ioctl handlers return -errno on linux and errno on
*BSD. Instead, just return -errno in shared code, and flip sign on return from
shared code to *BSD code.
Ben Skeggs
Dave Airlie
Eric Anholt