Now that the DP madness is cleared out, this is all only per-platform.
So move it out from the intel clock limits structure.

While at it drop the intel prefix on the static functions, call the
vtable entry find_dpll (since it's for the display pll) and rip out
the now unnecessary forward declarations.

Note that the parameters of ->find_dpll are still unchanged, but they
eventually need to be moved over to just take in a pipe configuration.
But currently a lot of things are still missing from the pipe
configuration (reflock, output-specific dpll limits and preferences,
downclocked dotclock). So this will happen in a later step.

Note that intel_g4x_limit has a peculiar case where it selects
intel_limits_i9xx_sdvo as the limit. This is pretty bogus and also not
used since the only output types left are DP and native TV-out which
both use special pre-tuned dpll values.

v2: Re-add comment for the find_pll callback (requested by Paulo) and
elaborate on why the transformation is correct for g4x platforms (to
clarify a review question from Paulo). Double up on that by adding a
WARN as suggested by Paulo Zanoni on irc.

v3: Initialize limits to NULL since gcc is now unhappy.

v4: v2/3 will blow up with a NULL dereference in ->find_dpll for dp and
TV-out ports, spotted by Paulo on irc. So just give up on this madness for
now, and leave this to be fixed in a later patch.

v5: Since the ever-so-slight change for g4x might result in some dpll
parameter computation failing spuriously where before it didn't for
ports with preset dpll settings (DP & TV-out) override this. For
paranoia also do it in the ilk+ code.

Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Pineview is just different.

Also split out i9xx_clock from intel_clock and drop the now redundant
struct device * parameter.

Note that in this patch I kill an XXX comment about 100MHz clocks. I
couldn't figure out what this is about, and we don't seem to have any
bug reports about this either. I suspect that it's a remnant from when
the i9xx and ilk+ modeset code was all in the same file since ilk+
does indeed have a 100MHz clock. So I've just killed it to stop the
cargo-culting.
Reviewed-by: NPaulo Zanoni <przanoni@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since this is run in the compute config stage we need to check
the new_ pointers, i.e the stage output routing, not the current
modeset layout. Also there was a little logic bug in properly skipping
connectors: The old code did not skip any unused connectors and so
clamped to whatever was left in there (usually 0 if that connector
hasn't seen a EDID 1.4 screen ever since boot-up).

This has been broken when moving the pipe bpp selection in

commit 4e53c2e0
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Mar 27 00:44:58 2013 +0100

    drm/i915: precompute pipe bpp before touching the hw

To avoid too much casting switch from drm_ to intel_ types.

Also add a bit of debug output to help reconstructing what's going
on.

v2: Try to clarify this a bit:
- s/pipe_config_set_bpp/compute_baseline_pipe_bpp/ to make it clearer
  at which stage this function is run. Also add a comment about what
  it does.
- Extract the sink clamping into it's own function.

v3: Actually make it compile.

v4: Split out all the prep refactoring to make the bugfix stick out
really badly. Also elaborate a bit in the commit message about the
nature of the bugfix.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As a prep work to fix it up:
- Use intel_connector instead of drm_connector to avoid too much
  upcasting in the bugfix patch.
- Extract the connector bpp clamping from the loop-over-connectors
  logic.
- Bikeshed function names (to make it clearer that
  acompute_baseline_pipe_bpp runs in the compute stage of the modeset
  sequence) and add a comment to make it clearer what it does.

No functional change in this patch.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We only need to do them if the pipe is actually running and if the
framebuffers have changed. Removes two "wait for vblank timed out"
messages when doing a suspend/resume cycle on my i855gm.

v2: s/to_intel_ctrc(crtc)/intel_crtc/ spotted by Chris.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

People don't like typedefs these days. Eliminate their use from intel_fb.c.
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>

Use container_of() instead of a cast to get struct intel_fbdev
from struct drm_fb_helper.

Also populate the fb_info->par correctly with the drm_fb_helper pointer
instead of the intel_fbdev pointer.

There's no actual functional change since the drm_fb_helper happens to
be the first member inside intel_fbdev.
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>

Rework of per ring hangcheck made this obsolete.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Keep track of ring seqno progress and if there are no
progress detected, declare hang. Use actual head (acthd)
to distinguish between ring stuck and batchbuffer looping
situation. Stuck ring will be kicked to trigger progress.

This commit adds a hard limit for batchbuffer completion time.
If batchbuffer completion time is more than 4.5 seconds,
the gpu will be declared hung.

Review comment from Ben which nicely clarifies the semantic change:

"Maybe I'm just stating the functional changes of the patch, but in case
they were unintended here is what I see as potential issues:

1. "If ring B is waiting on ring A via semaphore, and ring A is making
   progress, albeit slowly - the hangcheck will fire. The check will
   determine that A is moving, however ring B will appear hung because
   the ACTHD doesn't move. I honestly can't say if that's actually a
   realistic problem to hit it probably implies the timeout value is too
   low.

2. "There's also another corner case on the kick. If the seqno = 2
   (though not stuck), and on the 3rd hangcheck, the ring is stuck, and
   we try to kick it... we don't actually try to find out if the kick
   helped"

v2: use atchd to detect stuck ring from loop (Ben Widawsky)

v3: Use acthd to check when ring needs kicking.
Declare hang on third time in order to give time for
kick_ring to take effect.

v4: Update commit msg
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Paste in Ben's review comment.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since it will be used for the global bound/unbound list with full PPGTT,
this helps clarify things for upcoming code rework.
Recommended-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we properly keep track of the pages_pin_count, then when we later add
multiple address spaces, the put_pages doesn't need any special checks
to be able to perform it's job.

CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Rebased on top of the fix for stolen memory pinning.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The way the stolen handling works is we take a pin on the backing pages,
but we never actually get a reference to the bo. On freeing objects
allocated with stolen memory, the final unref will end up freeing the
object with pinned pages count left. To enable an assertion to catch
bugs in this code path, this patch cleans up that remaining pin.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This makes it easier to catch leaks.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It's not terribly interesting to know that a parameter doesn't exist,
and it can get in the way of interesting messages, especially with the
staggered VECS merging as we've done.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It just prints whether it's supported/enabled/disabled. Feature
requested by the power management team.

v2: Checkpatch started complaining about seq_printf with 1 argument.
Requested-by: NKristen Accardi <kristen.c.accardi@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

IPS is still enabled by default. Feature requested by the power
management team.

This should also help testing the feature on some early pre-production
hardware where there were relationship problems between IPS and PSR.

v2: Rebase on top of the newest IPS implementation.
v3: Check i915_enable_ips at compute_config, not supports_ips, so the
    kernel parameter will be ignored at haswell_get_pipe_config.
Requested-by: NKristen Accardi <kristen.c.accardi@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Intermediate Pixel Storage is a feature that should reduce the number
of times the display engine wakes up memory to read pixels, so it
should allow deeper PC states. IPS can only be enabled on ULT pipe A
with 8:8:8 pipe pixel formats.

With eDP 1920x1080 and correct watermarks but without FBC this moves
my PC7 residency from 2.5% to around 38%.

v2: - It's tied to pipe A, not port A
    - Add pipe_config support (Chris)
    - Add some assertions (Chris)
    - Rebase against latest dinq
v3: - Don't ever set ips_enabled to false (Daniel)
    - Only check for ips_enabled at hsw_disable_ips (Daniel)
v4: - Add hsw_compute_ips_config (Daniel)
    - Use the new dump_pipe_config (Daniel)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we track the cpu transcoder we need accurately in the pipe
config we can finally fix up the transcoder check. With the current
code eDP on port D will be broken since we'd errornously cut the
power.

For reference see

commit 2124b72e
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Fri Mar 22 14:07:23 2013 -0300

    drm/i915: don't disable the power well yet

v2:
- Kill the now outdated comment (Paulo)
- Add the missing crtc->base.enabled check and consolidate it (Paulo)
- Smash all checks together, looks neater that way.

v3: Kill the unused encoder variable.

Cc: Takashi Iwai <tiwai@suse.de>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This will let userland only try to use the new ring
when the appropriate kernel is present
Signed-off-by: NXiang, Haihao <haihao.xiang@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A user can run batchbuffer via VEBOX ring.
Signed-off-by: NXiang, Haihao <haihao.xiang@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Removed rebase relic VECS ring from i915_gem_request_info (Damien)

v3: s/hsw/hws in debugfs which I introduced in v2 (Jon)
Signed-off-by: NXiang, Haihao <haihao.xiang@intel.com>
[Order changed, and modified by]
CC:  "Bloomfield, Jon" <jon.bloomfield@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Similar to a patch originally written by:

v2: Reversed the meanings of masked and enabled (Haihao)
Made non-destructive writes in case enable/disabler rps runs first
(Haihao)

v3: Reword error message (Damien)
Modify postinstall to do the right thing based on previous fixup. (Ben)

CC: Xiang, Haihao <haihao.xiang@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Use the correct lock to protect PM interrupt regs, this was
accidentally lost from earlier (Haihao)
Fix return types (Ben)
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The motivation here is we're going to add some new interrupt definitions
and handling outside of the GT interrupts which is all we've managed so
far (with some RPS exceptions). By consolidating the names in the future
we can make thing a bit cleaner as we don't need to define register
names twice, and we can leverage pretty decent overlap in HW registers
since ILK.

To explain briefly what is in the comments: there are two sets of
interrupt masking/enabling registers. At least so far, the definitions
of the two sets overlap. The old code setup distinct names for
interrupts in each set, ie. one for global, and one for ring. This made
things confusing when using the wrong defines in the wrong places.

rebase: Modified VLV bits

v2: Renamed GT_RENDER_MASTER to GT_RENDER_CS_MASTER (Damien)
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It's overkill on older gens, but it's useful for newer gens.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

PM interrupts have an expanded role on HSW. It helps route the EBOX
interrupts. This patch is necessary to make the existing code which
touches the mask, and enable registers more friendly to other code paths
that also will need these registers.

To be more explicit:
At preinstall all interrupts are masked and disabled. This implies that
preinstall should always happen before any enabling/disabling of RPS or
other interrupts.

The PMIMR is touched by the workqueue, so enable/disable touch IER and
IIR. Similarly, the code currently expects IMR has no use outside of the
RPS related interrupts so they unconditionally set 0, or ~0. We could
use IER in the workqueue, and IMR elsewhere, but since the workqueue
use-case is more transient the existing usage makes sense.

Disable RPS events:
IER := IER & ~GEN6_PM_RPS_EVENTS // Disable RPS related interrupts
IIR := GEN6_PM_RPS_EVENTS // Disable any outstanding interrupts

Enable RPS events:
IER := IER | GEN6_PM_RPS_EVENTS // Enable the RPS related interrupts
IIR := GEN6_PM_RPS_EVENTS // Make sure there were no leftover events
(really shouldn't happen)

v2: Shouldn't destroy PMIIR or PMIMR VEBOX interrupt state in
enable/disable rps functions (Haihao)

v3: Bug found by Chris where we were clearing the wrong bits at rps
disable.
    expanded commit message

v4: v3 was based off the wrong branch

v5: Added the setting of PMIMR because of previous patch update

CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

At the moment, these values are wiped out anyway by the rps
enable/disable. That will be changed in the next patch though.

v2: Add post install setup to address issue found by Damien in the next
patch.
replaced
WARN_ON(dev_priv->rps.pm_iir != 0);
with rps.pm_iir = 0;

With the v2 of this patch and the deferred pm enabling (which changed
since the original patches) we're now able to get PM interrupts before
we've brought up enabled rps. At this point in boot, we don't want to do
anything about it, so we simply ignore it. Since writing the original
assertion, the code has changed quite a bit, and I believe removing this
assertion is perfectly safe.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: I don't agree with the justification to drop the WARN and
added a FIXME to that effect.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just duplicates ironlake_irq_preinstall for now.

v2: Add new PCH_NOP check (Damien)
Add SDEIMR comment (Damien)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Update now outdated comment.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

HSW has some special requirements for the VEBOX. Splitting out the
interrupt handler will make the code a bit nicer and less error prone
when we begin to handle those.

The slight functional change in this patch (queueing work while holding
the spinlock) is intentional as it makes a subsequent patch a bit nicer.
The change should also only effect HSW platforms.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now we compute the results for both 1/2 and 5/6 partitioning and then
use hsw_find_best_result to choose which one to use.

With this patch, Haswell watermarks support should be in good shape.
The only improvement we're missing is the case where the primary plane
is disabled: we always assume it's enabled, so we take it into
consideration when calculating the watermarks.

v2: - Check the latency when finding the best result
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We were previously only setting the WM_PIPE registers, now we are
setting the LP watermark registers. This should allow deeper PC
states, resulting in power savings.

We're only using 1/2 data buffer partitioning for now.

v2: Merge both hsw_compute_pri_wm_* functions (Ville)
v3: - Simplify hsw_compute_wm_results (Ville)
    - Rebase due to changes on the previous patch
v4: Unconfuse wm_lp/level (Ville)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We were previously calling sandybridge_update_wm on HSW, but the SNB
function didn't really match the HSW specification, so we were just
writing the wrong values.

With this patch, the haswell_update_wm function will set the correct
values for the WM_PIPE registers, but it will still keep all the LP
watermarks disabled.

The patch may look a little bit over-complicated for now, but it's
because much of the infrastructure for setting the LP watermarks is
already in place, so we won't have too much code churn on the patch
that sets the LP watermarks.

v2: - Fix pixel_rate on panel fitter case (Ville)
    - Try to not overflow (Ville)
    - Remove useless variable (Ville)
    - Fix p->pri_horiz_pixels (Paulo)
v3: - Fix rounding errors on hsw_wm_method2 (Ville)
v4: - Fix memcmp bug (Paulo)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was accidentally broken in the south error interrupt handling
work:

commit 8664281b
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Fri Apr 12 17:57:57 2013 -0300

    drm/i915: report Gen5+ CPU and PCH FIFO underruns

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Add set_seqno which didn't exist before rebase (Haihao)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NXiang, Haihao <haihao.xiang@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The flag will be useful to help share code between IVB, and HSW as the
programming is similar in many places with this as one of the major
differences.
Signed-off-by: NXiang, Haihao <haihao.xiang@intel.com>
[Commit message + small fix by]
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Historically we considered the render ring to have special flush
semantics and everything else to fall under a more general umbrella.
Probably by coincidence more than anything we decided to make the bsd
ring have the default *other* flush. As the new vebox ring exposes, the
bsd ring is actually the weird one. Doing this allows us to call
gen6_ring_flush for the vebox because calling blt_ring_flush would be
weird...

This patch should have no functional change.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Like the other rings, the VECS supports semaphores. The semaphore stuff
is a bit wonky so this patch on it's own should be nice for review.

This patch should have no functional impact.

v2: Fix the English parts of clarification (again, register names were
right, text was reversed) (Damien)
Restore the still valid invariant. (Damien)
The bsd semaphore register should be MI_SEMAPHORE_SYNC_VVE (Damien)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The video enhancement command streamer is a new ring on HSW which does
what it sounds like it does. This patch provides the most minimal
inception of the ring.

In order to support a new ring, we need to bump the number. The patch
may look trivial to the untrained eye, but bumping the number of rings
is a bit scary. As such the patch is not terribly useful by itself, but
a pretty nice place to find issues during a bisection.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This replaces the existing MBOX update code with a more generalized
calculation for emitting mbox updates. We also create a sentinel for
doing the updates so we can more abstractly deal with the rings.

When doing MBOX updates the code must be aware of the /other/ rings.
Until now the platforms which supported semaphores had a fixed number of
rings and so it made sense for the code to be very specialized
(hardcoded).

The patch does contain a functional change, but should have no
behavioral changes.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Semaphores are tied very closely to the rings in the GPU. Trivial patch
adds comments to the existing code so that when we add new rings we can
include comments there as well. It also helps distinguish the ring to
semaphore mailbox interactions by using the ringname in the semaphore
data structures.

This patch should have no functional impact.

v2: The English parts (as opposed to register names) of the comments
were reversed. (Damien)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>