One of the costs of superioctl has been the need to perform relocations
inside the kernel. The cost of mapping the buffers to the CPU and writing
data is fairly high, especially if those buffers have been mapped and read
by the GPU.
If we assume that buffers don't move around very often, we can have the
client compute the relocations itself using the previous GPU address. When
that object doesn't move, the kernel can skip computing and writing the
updated data.
Here's a patch which adds a new field to struct drm_bo_info_req called
'presumed_offset', and a new DRM_BO_HINT_PRESUMED_OFFSET that is set when
this field has been filled in by the client.
There are two separate optimizations performed when the presumed_offset is
correct:
1. i915_exec_reloc checks to see if all previous buffer offsets were guessed
correctly. If so, there's no need for it to look at *any* of the
relocations for a buffer. When this happens, it skips the whole
relocation process, simply returning success.
2. i915_apply_reloc checks to see if the target buffer offset was guessed
correctly. If so, it skips mapping the relocatee, computing the
relocation and writing the value. If no relocations are needed, the
relocatee should never be mapped to the CPU, and so the kernel shouldn't
need to wait for any fences to pass.
If drmMinor >= 6, the intel DDX driver will enable vblank events on both
pipes. If drmMinor >= 10 on pre-965 chipsets, the intel DDX driver will
swap the pipe<->plane mapping to allow for framebuffer compression on
laptop screens. This means the secondary vblank counter (corresponding
to pipe B) will be incremented when vblank interrupts occur.
Now Mesa waits for vblank events on whichever plane has a greater
portion of the displayed window. So it will happly ask to wait for the
primary counter even though that one won't increment.
So we can fix this in either the DDX driver, Mesa or the kernel (though
I thought we already had several times).
Since current (and previous) userspace assumes it's talking about a pipe
== plane situation and now uses planes when talking to the kernel, we
should probably just hide the mapping details there (indeed they already
are hidden there for vblank swaps), which this patch does.
So as far as userland is concerned, whether we call things planes or
pipes is irrelevant, as long as kernel developers understand that
userland hands them planes and they have to figure out which pipe that
corresponds to (which will typically be the same on 965+ hardware and
reversed on pre-965 mobile chips).
This should work on all radeon but there is still many things todo:
- add crtc2
- tmds
- lvds
- add bios data table so we don't need to hardcode dac/crtc infos
- separate clock control to make power saving easier & cleaner
- tiling (warning tiling shouldn't be enable in double scan or interlace)
- surface reg manager (this goes along with tiling)
- suspend/resume hook
- avivo & r500 family support
- atom bios support (for posting card mostly)
- finish superioctl skeleton
- what else ? :)
so really want to get a list of modes per output not the global hammer list.
also we remove the mode ids and let the user pass back the full mode description
need to fix up add/remove mode for user modes now
This allow the user to retrieve a list of properties for an output.
Properties can either be 32-bit values or an enum with an associated name.
Range properties are to be supported.
This API is probably not all correct, I may make properties part of the general
resource get when I think about it some more.
So basically you can create properties and attached them to whatever outputs you want,
so it should be possible to create some generics and just attach them to every output.
Dave Airlie
Jakob Bornecrantz
Alan Hourihane
Keith Packard
Dave Airlie
José Fonseca
Jerome Glisse
Jesse Barnes
Kristian Høgsberg
Robert Noland
Robert Noland
Maarten Maathuis
Jiri Slaby
Dave Airlie
Eric Anholt
Robert Noland
Stephane Marchesin