If we happen to emit more than I915_MAX_WA_REGS workarounds, we will
currently discard them, not even emit the LRI. Not really what we want,
so warn loudly.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When entering intel_ring_emit_wa() with num_wa_regs equal to
I915_MAX_WA_REGS, we end up indexing the intel_wa_regs array beyond its
allocation.

Fix the check then.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Follow the BDW example and apply the workarounds touching registers
which are saved in the context image through LRIs in the new
ring->init_context() hook.

This makes Mesa much happier and eg. glxgears doesn't hang after
the first frame.

Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Add missing wa table initialization to avoid a functional
conflict with Arun's wa table debugfs support.]
Reviewed-by: N"Barbalho, Rafael" <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The workarounds that are applied are exported to a debugfs file;
this is used to verify their state after the test case (reset or
suspend/resume etc). This patch is only required to support i-g-t.
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For BDW workarounds are currently initialized in init_clock_gating() but
they are lost during reset, suspend/resume etc; this patch moves the WAs
that are part of register state context to render ring init fn otherwise
default context ends up with incorrect values as they don't get initialized
until init_clock_gating fn.

v2: Add workarounds to golden render state
This method has its own issues, first of all this is different for
each gen and it is generated using a tool so adding new workaround
and mainitaining them across gens is not a straightforward process.

v3: Use LRIs to emit these workarounds (Ville)
Instead of modifying the golden render state the same LRIs are
emitted from within the driver.

v4: Use abstract name when exporting gen specific routines (Chris)

For: VIZ-4092
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

According to spec FBC on BDW and HSW are identical without any gaps.
So let's copy the nuke and let FBC really start compressing stuff.

Without this patch we can verify with false color that nothing is being
compressed. With the nuke in place and false color it is possible
to see false color debugs.

Unfortunatelly on some rings like BCS on BDW we have to avoid Bits 22:18 on
LRIs due to a high risk of hung. So, when using Blt ring for frontbuffer rend
cache would never been cleaned and FBC would stop compressing buffer.
One alternative is to cache clean on software frontbuffer tracking.

v2: Fix rebase conflict.
v3: Do not clean cache on BCS ring. Instead use sw frontbuffer tracking.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we reset a ring after a hang, we have to make sure that we clear
out all queued Execlists requests.

v2: The ring is, at this point, already being correctly re-programmed
for Execlists, and the hangcheck counters cleared.

v3: Daniel suggests to drop the "if (execlists)" because the Execlists
queue should be empty in legacy mode (which is true, if we do the
INIT_LIST_HEAD).

v4: Do the pending intel_runtime_pm_put
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A subsequent patch will no longer initialize the aliasing ppgtt if we
have full ppgtt enabled, since we simply don't need that any more.

Unfortunately a few places check for the aliasing ppgtt instead of
checking for ppgtt in general. Fix them up.

One special case are the gtt offset and size macros, which have some
code to remap the aliasing ppgtt to the global gtt. The aliasing ppgtt
is _not_ a logical address space, so passing that in as the vm is
plain and simple a bug. So just WARN about it and carry on - we have a
gracefully fall-through anyway if we can't find the vma.
Reviewed-by: NMichel Thierry <michel.thierry@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Same as the legacy-style ring->flush.

v2: The BSD invalidate bit still exists in GEN8! Add it for the VCS
rings (but still consolidate the blt and bsd ring flushes into one).
This was noticed by Brad Volkin.

v3: The command for BSD and for other rings is slightly different:
get it exactly the same as in gen6_ring_flush + gen6_bsd_ring_flush
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Well, new-ish: if all this code looks familiar, that's because it's
a clone of the existing submission mechanism (with some modifications
here and there to adapt it to LRCs and Execlists).

And why did we do this instead of reusing code, one might wonder?
Well, there are some fears that the differences are big enough that
they will end up breaking all platforms.

Also, Execlists offer several advantages, like control over when the
GPU is done with a given workload, that can help simplify the
submission mechanism, no doubt. I am interested in getting Execlists
to work first and foremost, but in the future this parallel submission
mechanism will help us to fine tune the mechanism without affecting
old gens.

v2: Pass the ringbuffer only (whenever possible).
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Appease checkpatch. Again. And drop the legacy sarea gunk
that somehow crept in.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Logical rings do not need most of the initialization their
legacy ringbuffer counterparts do: we just need the pipe
control object for the render ring, enable Execlists on the
hardware and a few workarounds.

v2: Squash with: "drm/i915: Extract pipe control fini & make
init outside accesible".
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Make checkpatch happy.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Allocate and populate the default LRC for every ring, call
gen-specific init/cleanup, init/fini the command parser and
set the status page (now inside the LRC object). These are
things all engines/rings have in common.

Stopping the ring before cleanup and initializing the seqnos
is left as a TODO task (we need more infrastructure in place
before we can achieve this).

v2: Check the ringbuffer backing obj for ring_is_initialized,
instead of the context backing obj (similar, but not exactly
the same).
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Any given ringbuffer is unequivocally tied to one context and one engine.
By setting the appropriate pointers to them, the ringbuffer struct holds
all the infromation you might need to submit a workload for processing,
Execlists style.

v2: Drop ring->ctx since that looks terribly ill-defined for legacy
ringbuffer submission.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v1)
Acked-by: Damien Lespiau <damien.lespiau@intel.com> (v2)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As we have said a couple of times by now, logical ring contexts have
their own ringbuffers: not only the backing pages, but the whole
management struct.

In a previous version of the series, this was achieved with two separate
patches:
drm/i915/bdw: Allocate ringbuffer backing objects for default global LRC
drm/i915/bdw: Allocate ringbuffer for user-created LRCs
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During ring initialisation, sometimes we observe, though not in
production hardware, that the idle flag is not set even though the ring
is empty. Double check before giving up.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Doing a 1s wait (tops) with the cpu is a bit excessive. Tune it down
like everything else in that code.

v2: Also insert the missing space Chris spotted.

Cc: Naresh Kumar Kachhi <naresh.kumar.kachhi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Withtout this, ring initialization fails reliabily during resume with

	[drm:init_ring_common] *ERROR* render ring initialization failed ctl 0001f001 head ffffff8804 tail 00000000 start 000e4000

This is not a complete fix, but it is verified to make the ring
initialization failures during resume much less likely.

We were not able to root-cause this bug (likely HW-specific to Gen4 chips)
yet. This is therefore used as a ducttape before problem is fully
understood and proper fix created, so that people don't suffer from
completely unusable systems in the meantime.

The discussion and debugging is happening at

	https://bugs.freedesktop.org/show_bug.cgi?id=76554Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On Broadwell, any PIPE_CONTROL with the "State Cache Invalidate" bit set
must be preceded by a PIPE_CONTROL with the "CS Stall" bit set.

Documented on the BSpec 3D workarounds page.
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NKenneth Graunke <kenneth@whitecape.org>
[vsyrjala: add chv w/a note too]
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We'll want to reuse this for a workaround.
Signed-off-by: NKenneth Graunke <kenneth@whitecape.org>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Rmove now unused int.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Traditionally we use genX_ for GT/render stuff and the codenames for
display stuff. But the gt and pm interrupt handling functions on
gen5/6+ stuck out as exceptions, so convert them.

Looking at the diff this nicely realigns our ducks since almost all
the callers are already platform-specific functions following the
genX_ pattern.

Spotted while reviewing some internal rps patches.

No function change in this patch.
Acked-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On g33, the documentation states

"HWS_PGA:
 Format = Bits 28:12 of graphics memory address (bits 31:29 MBZ)."

which translates to that the address of the HWS must be below 256MiB,
which is conveniently the mappable aperture.

This also appears to be true (but not documented as so) for gen4 and
gen5. To generalise we force it into the low mappable region for all
non-LLC platforms. If we locate the HWS at the top of the GTT the
machine will hard hang during boot (fails on pnv, gm45, ilk and byt,
but works on snb, ivb, hsw).

v2: Add comments to explain why use PIN_MAPPABLE even though we have
    no intention of mapping the object. (Ville)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It's simple enough that it doesn't need to know anything about the
engine.

Trivial change.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

More prep work: with Execlists, we are going to start creating a lot
of extra ringbuffers soon, so these functions are handy.

No functional changes.

v2: rename allocate/destroy_ring_buffer to alloc/destroy_ringbuffer_obj
because the name is more meaningful and to mirror a similar function in
the context world: i915_gem_alloc_context_obj(). Change suggested by Brad
Volkin.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As Ville points out, it's possible/probable we don't actually need this.
Potentially, this validates the letter of the spec, and not the spirit.

Ville:
> I discussed this on irc w/ Ben, and I was suggesting we don't need to
> poll. Polling apparently can be used as a workaround for certain
> hardware issues, but it looks like those issues shouldn't affect us,
> for the momemnt at least. So my suggestion was to try w/o polling
> first (since there could be some power cost to polling) and add the
> poll bit if problems arise.

Rodrigo: Spec suggests this as an W/A for GT3. However semaphores didn't
worked in my BDW GT2 on Signal Mode. So pool mode is definitely needed.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Semaphore waits use a new instruction, MI_SEMAPHORE_WAIT. The seqno to
wait on is all well defined by the table in the previous patch. There is
nothing else different from previous GEN's semaphore synchronization
code.

v2: Update macros to not require the other ring's ring->id (Chris)

v3: Add missing VCS2 gen8_ring_wait init besides
    s/ring_buffer/engine_cs (Rodrigo)
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Semaphore signalling works similarly to previous GENs with the exception
that the per ring mailboxes no longer exist. Instead you must define
your own space, somewhere in the GTT.

The comments in the code define the layout I've opted for, which should
be fairly future proof. Ie. I tried to define offsets in abstract terms
(NUM_RINGS, seqno size, etc).

NOTE: If one wanted to move this to the HWSP they could. I've decided
one 4k object would be easier to deal with, and provide potential wins
with cache locality, but that's all speculative.

v2: Update the macro to not need the other ring's ring->id (Chris)
Update the comment to use the correct formula (Chris)

v3: Move the macros the ringbuffer.h to prevent churn in next patch
(Ville)

v4: Fixed compilation rebase conflict
commit 1ec9e26d
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Feb 14 14:01:11 2014 +0100

    drm/i915: Consolidate binding parameters into flags

v5: VCS2 rebase
Replace hweight_long with hweight32

v6 (Rodrigo): * Add missed VC2 gen8 ring signal init
   	      * fixing conflicst on rebase
    	      * minor fixes on address table
	      * remove WARN_ON
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
[danvet: s/BUG_ON/WARN_ON/]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the ring mask we now have an easy way to know the number of rings
in the system, and therefore can accurately predict the number of dwords
to emit for semaphore signalling. This was not possible (easily)
previously.

There should be no functional impact, simply fewer instructions emitted.

While we're here, simply do the round up to 2 instead of the fancier
rounding we did before, which rounding up per mbox, ie 4. This also
allows us to drop the unnecessary MI_NOOP, so not really 4, 3.

v2: Use 3 dwords instead of 4 (Ville)
Do the proper calculation to get the number of dwords to emit (Ville)
Conditionally set .sync_to when semaphores are enabled (Ville)

v3: Rebased on VCS2
Replace hweight_long with hweight32 (Ville)

v4: Pull out the accidentally squashed hunk from the next patch after
rebase (Daniel).

v5: Fix conflict after rebase (Rodrigo)
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Gen8 has already had some differentiation with how it handles rings.
Semaphores bring yet more differences, and now is as good a time as any
to do the split.

Also, since gen8 doesn't actually use semaphores up until this point,
put the proper "NULL" values in for the mbox info.

v2: v1 had a stale commit message

v3: Move everything in the is_semaphore_enabled() check

v4: VCS2 rebase
Remove double assignment of signal in render ring (Ville)

v5: Adding missed VCS2 signal init on gen8+ (Rodrigo)
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It just fix a typo.

v2: removing underscore to let this like all other ring names (Oscar)

Cc: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by (v1): Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This commit add check for return value of init_ring_common() in the
init_render_ring(). Now, when failure is detected the error code is
propagated to the caller instead of being ignored.
Signed-off-by: NKonrad Zapalowicz <bergo.torino@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This adds support for a write-enable bit in the entry of GTT.
This is handled via a read-only flag in the GEM buffer object which
is then used to see how to set the bit when writing the GTT entries.
Currently by default the Batch buffer & Ring buffers are marked as read only.

v2: Moved the pte override code for read-only bit to 'byt_pte_encode'. (Chris)
    Fixed the issue of leaving 'gt_old_ro' as unused. (Chris)

v3: Removed the 'gt_old_ro' field, now setting RO bit only for Ring Buffers(Daniel).

v4: Added a new 'flags' parameter to all the pte(gen6) encode & insert_entries functions,
    in lieu of overloading the cache_level enum (Daniel).

v5: Removed the superfluous VLV check & changed the definition location of PTE_READ_ONLY flag (Imre)
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

These do not exist anymore.

Spotted while reading through intel_ringbuffer.c
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Gen2 doesn't have the ring idle/stop bits in the SCPD/MI_MODE register,
so don't go spewing warnings about the state of those bits.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Manual cleanup after the previous Coccinelle script.

Yes, I could write another Coccinelle script to do this but I
don't want labor-replacing robots making an honest programmer's
work obsolete (also, I'm lazy).
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This refactoring has been performed using the following Coccinelle
semantic script:

    @@
    struct intel_engine_cs r;
    @@
    (
    - (r).obj
    + r.buffer->obj
    |
    - (r).virtual_start
    + r.buffer->virtual_start
    |
    - (r).head
    + r.buffer->head
    |
    - (r).tail
    + r.buffer->tail
    |
    - (r).space
    + r.buffer->space
    |
    - (r).size
    + r.buffer->size
    |
    - (r).effective_size
    + r.buffer->effective_size
    |
    - (r).last_retired_head
    + r.buffer->last_retired_head
    )

    @@
    struct intel_engine_cs *r;
    @@
    (
    - (r)->obj
    + r->buffer->obj
    |
    - (r)->virtual_start
    + r->buffer->virtual_start
    |
    - (r)->head
    + r->buffer->head
    |
    - (r)->tail
    + r->buffer->tail
    |
    - (r)->space
    + r->buffer->space
    |
    - (r)->size
    + r->buffer->size
    |
    - (r)->effective_size
    + r->buffer->effective_size
    |
    - (r)->last_retired_head
    + r->buffer->last_retired_head
    )

    @@
    expression E;
    @@
    (
    - LP_RING(E)->obj
    + LP_RING(E)->buffer->obj
    |
    - LP_RING(E)->virtual_start
    + LP_RING(E)->buffer->virtual_start
    |
    - LP_RING(E)->head
    + LP_RING(E)->buffer->head
    |
    - LP_RING(E)->tail
    + LP_RING(E)->buffer->tail
    |
    - LP_RING(E)->space
    + LP_RING(E)->buffer->space
    |
    - LP_RING(E)->size
    + LP_RING(E)->buffer->size
    |
    - LP_RING(E)->effective_size
    + LP_RING(E)->buffer->effective_size
    |
    - LP_RING(E)->last_retired_head
    + LP_RING(E)->buffer->last_retired_head
    )

Note: On top of this this patch also removes the now unused ringbuffer
fields in intel_engine_cs.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
[danvet: Add note about fixup patch included here.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As advanced by the previous patch, the ringbuffers and the engine
command streamers belong in different structs. This is so because,
while they used to be tightly coupled together, the new Logical
Ring Contexts (LRC for short) have a ringbuffer each.

In legacy code, we will use the buffer* pointer inside each ring
to get to the pertaining ringbuffer (the actual switch will be
done in the next patch). In the new Execlists code, this pointer
will be NULL and we will use instead the one inside the context
instead.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In the upcoming patches we plan to break the correlation between
engine command streamers (a.k.a. rings) and ringbuffers, so it
makes sense to refactor the code and make the change obvious.

No functional changes.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We implement the following workarounds:
* WaDisableAsyncFlipPerfMode:chv
* WaProgramMiArbOnOffAroundMiSetContext:chv

v2: Drop WaDisableSemaphoreAndSyncFlipWait note
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we dont have semaphores enabled, we allocate 4
dwords for signalling. But end up emitting more regardless.

Fix this by bailing out early if semaphores are not enabled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78274
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78283Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is missing in:

commit 78325f2d
Author: Ben Widawsky <benjamin.widawsky@intel.com>
Date:   Tue Apr 29 14:52:29 2014 -0700

    drm/i915: Virtualize the ringbuffer signal func

Looks to me like a rebase side-effect...
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>