The LRC submission code requires a request for tracking purposes. It does not
actually require that request to 'complete' it simply uses it for keeping hold
of reference counts on contexts and such like.

Previously, the fall back path of polling for space in the ring would start by
submitting any outstanding work that was sat in the buffer. This submission was
not done as part of the request that that work was owned by because that would
lead to complications with the request being submitted twice. Instead, a null
request structure was passed in to the submit call and a fake one was created.

That fall back path has long since been obsoleted and has now been removed. Thus
there is never any need to fake up a request structure. This patch removes that
code. A couple of sanity check warnings are added as well, just in case.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <thomas.daniel@intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In _i915_add_request(), the request is associated with a userland client.
Specifically it is linked to the 'file' structure and the current user process
is recorded. One problem here is that the current user process is not
necessarily the same as when the request was submitted to the driver. This is
especially true when the GPU scheduler arrives and decouples driver submission
from hardware submission. Note also that it is only in the case where the add
request comes from an execbuff call that there is a client to associate. Any
other add request call is kernel only so does not need to do it.

This patch moves the client association into a separate function. This is then
called from the execbuffer code path itself at a sensible time. It also removes
the now redundant 'file' pointer from the add request parameter list.

An extra cleanup of the client association is also added to the request clean up
code for the eventuality where the request is killed after association but
before being submitted (e.g. due to out of memory error somewhere). Once the
submission has happened, the request is on the request list and the regular
request list removal will clear the association. Note that this still needs to
happen at this point in time because the request might be kept floating around
much longer (due to someone holding a reference count) and the client should not
be worrying about this request after it has been retired.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The outstanding_lazy_request is no longer used anywhere in the driver.
Everything that was looking at it now has a request explicitly passed in from on
high. Everything that was relying upon it behind the scenes is now explicitly
creating/passing/submitting its own private request. Thus the OLR can be
removed.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Much of the driver has now been converted to passing requests around instead of
rings/ringbufs/contexts. Thus the function for retreiving the request from a
ring (i.e. the OLR) is no longer used and can be removed.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that the *_ring_begin() functions no longer call the request allocation
code, it is finally safe for the request allocation code to call *_ring_begin().
This is important to guarantee that the space reserved for the subsequent
i915_add_request() call does actually get reserved.

v2: Renamed functions according to review feedback (Tomas Elf).

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that everything above has been converted to use requests,
intel_logical_ring_begin() can be updated to take a request instead of a
ringbuf/context pair. This also means that it no longer needs to lazily allocate
a request if no-one happens to have done it earlier.

Note that this change makes the execlist signature the same as the legacy
version. Thus the two functions could be merged into a ring->begin() wrapper if
required.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that everything above has been converted to use requests, intel_ring_begin()
can be updated to take a request instead of a ring. This also means that it no
longer needs to lazily allocate a request if no-one happens to have done it
earlier.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated intel_ring_cacheline_align() to take a request instead of a ring.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the various ring->signal() implementations to take a request instead of
a ring. This removes their reliance on the OLR to obtain the seqno value that
should be used for the signal.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the ring->sync_to() implementations to take a request instead of a ring.
Also updated the tracer to include the request id.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
[danvet: Rebase since I didn't merge the patch which added ->uniq.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the ring->emit_bb_start() implementation to take a request instead of a
ringbuf/context pair.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the various ring->dispatch_execbuffer() implementations to take a
request instead of a ring.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the ring->emit_request() implementation to take a request instead of a
ringbuf/request pair. Also removed its use of the OLR for obtaining the
request's seqno.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the various ring->add_request() implementations to take a request
instead of a ring. This removes their reliance on the OLR to obtain the seqno
value that the request should be tagged with.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the various ring->emit_flush() implementations to take a request instead
of a ringbuf/context pair.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated intel_emit_post_sync_nonzero_flush(), gen7_render_ring_cs_stall_wa() and
gen8_emit_pipe_control() to take requests instead of rings.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the various ring->flush() functions to take a request instead of a ring.
Also updated the tracer to include the request id.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
[danvet: Rebase since I didn't merge the addition of req->uniq.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the switch_mm() code paths to take a request instead of a ring. This
includes the myriad *_mm_switch functions themselves and a bunch of PDP related
helper functions.

v2: Rebased to newer tree.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the *_ring_flush_all_caches() functions to take requests instead of
rings or ringbuf/context pairs.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the *_ring_workarounds_emit() functions to take requests instead of
ring/context pairs.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated *_ring_invalidate_all_caches(), i915_reset_gen7_sol_offsets() and
i915_emit_box() to take request structures instead of ring or ringbuf/context
pairs.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated mi_set_context() to take a request structure instead of a ring and
context pair.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Converted i915_gem_l3_remap() to take a request structure instead of a ring.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that everything above has been converted to use request structures, it is
possible to update the lower level move_to_active() functions to be request
based as well.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that all callers of i915_add_request() have a request pointer to hand, it is
possible to update the add request function to take a request pointer rather
than pulling it out of the OLR.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the display page flip code to do explicit request creation and
submission rather than relying on the OLR and just hoping that the request
actually gets submitted at some random point.

The sequence is now to create a request, queue the work to the ring, assign the
known request to the flip queue work item then actually submit the work and post
the request.

Note that every single flip function used to finish with
'__intel_ring_advance(ring);'. However, immediately after they return there is
now an add request call which will do the advance anyway. Thus the many
duplicate advance calls have been removed.

v2: Updated commit message with comment about advance removal.

v3: The request can now be allocated by the _sync() code earlier on. Thus the
page flip path does not necessarily need to allocate a new request, it may be
able to re-use one.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The overlay update code path to do explicit request creation and submission
rather than relying on the OLR to do the right thing.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The plan is to pass requests around as the basic submission tracking structure
rather than rings and contexts. This patch updates the i915_gem_object_sync()
code path.

v2: Much more complex patch to share a single request between the sync and the
page flip. The _sync() function now supports lazy allocation of the request
structure. That is, if one is passed in then that will be used. If one is not,
then a request will be allocated and passed back out. Note that the _sync() code
does not necessarily require a request. Thus one will only be created until
certain situations. The reason the lazy allocation must be done within the
_sync() code itself is because the decision to need one or not is not really
something that code above can second guess (except in the case where one is
definitely not required because no ring is passed in).

The call chains above _sync() now support passing a request through which most
callers passing in NULL and assuming that no request will be required (because
they also pass in NULL for the ring and therefore can't be generating any ring
code).

The exeception is intel_crtc_page_flip() which now supports having a request
returned from _sync(). If one is, then that request is shared by the page flip
(if the page flip is of a type to need a request). If _sync() does not generate
a request but the page flip does need one, then the page flip path will create
its own request.

v3: Updated comment description to be clearer about 'to_req' parameter (Tomas
Elf review request). Rebased onto newer tree that significantly changed the
synchronisation code.

v4: Updated comments from review feedback (Tomas Elf)

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated the two render_state_init() functions to take a request pointer instead
of a ring. This removes their reliance on the OLR.

v2: Rebased to newer tree.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that everything above has been converted to use requests, it is possible to
update init_context() to take a request pointer instead of a ring/context pair.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In execlist mode, context initialisation is deferred until first use of the
given context. This is because execlist mode has per ring context state and thus
many more context storage objects than legacy mode and many are never actually
used. Previously, the initialisation commands were written to the ring and
tagged with some random request structure via the OLR. This seemed to be causing
a null pointer deference bug under certain circumstances (BZ:88865).

This patch adds explicit request creation and submission to the deferred
initialisation code path. Thus removing any reliance on or randomness caused by
the OLR.

Note that it should be possible to move the deferred context creation until even
later - when the context is actually switched to rather than when it is merely
validated. This would allow the initialisation to be done within the request of
the work that is wanting to use the context. Hence, the extra request that is
created, used and retired just for the context init could be removed completely.
However, this is left for a follow up patch.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updated do_switch() to take a request pointer instead of a ring/context pair.

v2: Removed some overzealous req-> dereferencing.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that the request is guaranteed to specify the context, it is possible to
update the context switch code to use requests rather than ring and context
pairs. This patch updates i915_switch_context() accordingly.

Also removed the warning that the request's context must match the last context
switch's context. As the context switch now gets the context object from the
request structure, there is no longer any scope for the two to become out of
step.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The final step in removing the OLR from i915_gem_init_hw() is to pass the newly
allocated request structure in to each step rather than passing a ring
structure. This patch updates both i915_ppgtt_init_ring() and
i915_gem_context_enable() to take request pointers.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that a single per ring loop is being done for all the different
intialisation steps in i915_gem_init_hw(), it is possible to add proper request
management as well. The last remaining issue is that the context enable call
eventually ends up within *_render_state_init() and this does its own private
_i915_add_request() call.

This patch adds explicit request creation and submission to the top level loop
and removes the add_request() from deep within the sub-functions.

v2: Updated for removal of batch_obj from add_request call in previous patch.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The render state initialisation code does an explicit i915_add_request() call to
commit the init commands. It was passing in the initialisation batch buffer to
add_request() as the batch object parameter. However, the batch object entry in
the request structure (which is all that parameter is used for) is meant for
keeping track of user generated batch buffers for blame tagging during GPU
hangs.

This patch clears the batch object parameter so that kernel generated batch
buffers are not tagged as being user generated.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The start of day context initialisation code in i915_gem_context_enable() loops
over each ring and calls the legacy switch context or the execlist init context
code as appropriate.

This patch moves the ring looping out of that function in to the top level
caller i915_gem_init_hw(). This means the a single pass can be made over all
rings doing the PPGTT, L3 remap and context initialisation of each ring
altogether.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The i915_gem_init_hw() function calls a bunch of smaller initialisation
functions. Multiple of which have generic sections and per ring sections. This
means multiple passes are done over the rings. Each pass writes data to the ring
which floats around in that ring's OLR until some random point in the future
when an add_request() is done by some random other piece of code.

This patch breaks i915_ppgtt_init_hw() in two with the per ring initialisation
now being done in i915_ppgtt_init_ring(). The ring looping is now done at the
top level in i915_gem_init_hw().

v2: Fix dumb loop variable re-use.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Tomas Elf <tomas.elf@intel.com> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Added explicit request creation and submission to the GPU idle code path.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In order to explcitly track all GPU work (and completely remove the outstanding
lazy request), it is necessary to add extra i915_add_request() calls to various
places. Some of these do not need the implicit cache flush done as part of the
standard batch buffer submission process.

This patch adds a flag to _add_request() to specify whether the flush is
required or not.

For: VIZ-5115
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTomas Elf <tomas.elf@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>