With intel_pipe_update begin/end we ensure that the mmio updates
don't run during vblank interrupt, using the hw counter we can
be sure that when current vblank count != vblank count at the time
of pipe_update_end the mmio update is complete.

This allows us to use mmio updates on all platforms, using the
update_plane call.

With Chris Wilson's patch to skip waiting for vblanks for
legacy_cursor_update this potentially leaves a small race
condition, in which update_plane can be called with a freed
crtc_state. Because of this commit acf4e84d
("drm/i915: Avoid stalling on pending flips for legacy cursor updates")
is temporarily reverted.

Changes since v1:
- Split out the flip_work rename.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-9-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

This reverts commit acf4e84d.
Unfortunately this breaks the next commit with a use-after-free, so
temporarily revert until we can apply a solution.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-8-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

Rename intel_unpin_work to intel_flip_work and use it for mmio flips
and unpinning. Use flip_queued_req to hold the wait request in the
mmio case, and the vblank counter from intel_crtc_get_vblank_counter.

MMIO flips get their own path through intel_finish_page_flip_mmio,
handled on vblank. CS page flips go through *_cs.

Changes since v1:
- Clean up destinction between MMIO and CS flips.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-7-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

This uses the newly created drm_accurate_vblank_count_and_time to accurately
get a vblank count when the hw counter is unavailable.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-6-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

Instead of calling prepare_flip right before calling finish_page_flip
do everything from prepare_page_flip in finish_page_flip.

Putting prepare and finish page_flip in a single step removes the need
for INTEL_FLIP_COMPLETE, so it can be removed. This simplifies the code
slightly.

Changes since v1:
- Invert if case to simplify code.
- Add missing barrier.
- Reword commit message.
Changes since v2:
- intel_page_flip_plane is removed.
- work->pending is turned into a bool.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-5-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

This function is duplicated with intel_finish_page_flip,
and is only ever used from planes that could use the
other function anyway.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-4-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

Both intel_unpin_work.pending and intel_unpin_work.enable_stall_check
were used to see if work should be enabled. By only using pending
some special cases are gone, and access to unpin_work can be simplified.

A flip could previously be queued before
stallcheck was active. With the addition of the pending member
enable_stall_check became obsolete and can thus be removed.

Use this to only access work members untilintel_mark_page_flip_active
is called, or intel_queue_mmio_flip is used. This will prevent
use-after-free, and makes it easier to verify accesses.

Changes since v1:
- Reword commit message.
- Do not access unpin_work after intel_mark_page_flip_active.
- Add the right memory barriers.
Changes since v2:
- atomic_read() needs a full smp_rmb.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-3-git-send-email-maarten.lankhorst@linux.intel.comReviewed-by: NPatrik Jakobsson <patrik.jakobsson@linux.intel.com>

This patch resizes the GuC WOPCM (specifically on BXT)
so that the GuC and RC6 memory spaces do not overlap.

v2:
    Made calculation of WOPCM size into a separate function,
    so that it's consistent between the firmware size-check
    and the register-programming operations [Dave Gordon].

Issue: https://jira01.devtools.intel.com/browse/VIZ-6638Signed-off-by: NPeter Antoine <peter.antoine@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NNick Hoath <nicholas.hoath@intel.com>
Tested-by: NNick Hoath <nicholas.hoath@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463494365-26330-1-git-send-email-david.s.gordon@intel.com

- Unconditionally add plane states. Core helpers would have done this
  in drm_atomic_helper_check_modeset, doing it once more won't cause
  harm and is less fragile.

- Simplify the continue logic when disabling a pipe.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462779085-2458-1-git-send-email-daniel.vetter@ffwll.ch

In CABC (Content Adaptive Brightness Control) content grey level
scale can be increased while simultaneously decreasing
brightness of the backlight to achieve same perceived brightness.

The CABC is not standardized and panel vendors are free to follow
their implementation. The CABC implementaion here assumes that the
panels use standard SW register for control.

CABC is supported only when the PWM source for backlight is
from the panel.

v2 by Jani: rebase, renames, check cabc support earlier, etc.
Signed-off-by: NDeepak M <m.deepak@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/883faade74d2e598b143221ccc7df6daf4393a13.1461676337.git.jani.nikula@intel.com

If the source of the backlight PWM is from the
panel then the PWM can be controlled by DCS
command, this patch adds the support to
enable/disbale panel PWM, control backlight level
etc...

v2: Moving the CABC bkl functions to new file.(Jani)

v3: Rebase

v4: Rebase

v5: Use mipi_dsi_dcs_write() instead of mipi_dsi_dcs_write_buffer() (Jani)
    Move DCS macro`s to include/video/mipi_display.h (Jani)

v6: Rename the file to intel_dsi_panel_pwm.c
    Removing the CABC operations

v7 by Jani: renames, rebases, etc.

v8 by Jani: s/INTEL_BACKLIGHT_CABC/INTEL_BACKLIGHT_DSI_DCS/

v9 by Jani: rename init function to intel_dsi_dcs_init_backlight_funcs

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Yetunde Adebisi <yetundex.adebisi@intel.com>
Signed-off-by: NDeepak M <m.deepak@intel.com>
Reviewed-by: NYetunde Adebisi <yetundex.adebisi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/71238a4b14b8c3a6c04070c789f09f1b4bc00a15.1461676337.git.jani.nikula@intel.com

Also make the code more readable.
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463148278-23193-2-git-send-email-jani.nikula@intel.com

Under full-ppgtt, access to the global GTT is carefully regulated
through hardware functions (i.e. userspace cannot read and write to
arbitrary locations in the GGTT via the GPU). With this restriction in
place, we can forgo clearing stale entries from the GGTT as they will
not be accessed.

For aliasing-ppgtt, we could almost do the same except that we do allow
userspace access to the global-GTT via execbuf in order to workraound
some quirks of certain instructions. (This execbuf path is filtered out
with EINVAL on full-ppgtt.)

The most dramatic effect this will have will be during resume, as with
full-ppgtt the GGTT is only used sparingly.

References: https://bugs.freedesktop.org/show_bug.cgi?id=94722Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: David Weinehall <david.weinehall@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Tested-by: NDavid Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463207195-22076-4-git-send-email-chris@chris-wilson.co.uk

Now that we mark the object domains for having been restored from the
hibernation image, we not need to flush everything during resume and
can instead rely on the normal domain tracking to flush only when
required. The only caveat here are objects that are pinned for use by
the hardware, whose contents must be coherent for when the device
resumes reading from then (shortly afterwards with the driver assuming
the objects are in the correct domain).

References: https://bugs.freedesktop.org/show_bug.cgi?id=94722Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: David Weinehall <david.weinehall@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Tested-by: NDavid Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463207195-22076-3-git-send-email-chris@chris-wilson.co.uk

When creating the hibernation image, the CPU will read the pages of all
objects and thus conflict with our domain tracking. We need to update
our domain tracking to accurately reflect the state on restoration.

v2: Perform the domain tracking inside freeze, before the image is
written, rather than upon restoration.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: David Weinehall <david.weinehall@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463207195-22076-2-git-send-email-chris@chris-wilson.co.uk

Currently for handling the extra hibernation phases we just call the
equivalent suspend/resume phases. In the next couple of patches, I wish
to specialise the hibernation phases to reduce the amount of work
required for handling GEM objects.

v2: There are more! Don't forget the freeze phases.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: David Weinehall <david.weinehall@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463207195-22076-1-git-send-email-chris@chris-wilson.co.uk

When we resume the watermark register may contain some BIOS leftovers,
or just the hardware reset values. We should ignore those as the
pipes will be off anyway, and so frobbing around with intermediate
watermarks doesn't make much sense.

In fact I think we should just throw the skip_intermediate_wm flag
out, and instead properly sanitize the "active" watermarks to match
the current plane and pipe states. The actual wm state readout might
also need a bit of work. But for now, let's continue with the
skip_intermediate_wm to keep the fix more minimal.

Fixes this sort of errors on resume
[drm:ilk_validate_pipe_wm] LP0 watermark invalid
[drm:intel_crtc_atomic_check] No valid intermediate pipe watermarks are possible
[drm:intel_display_resume [i915]] *ERROR* Restoring old state failed with -22
and a boatload of subsequent modeset BAT fails on my ILK.

v2:
 - Rebase; the SKL atomic WM patches that just landed changed the WM
   structure fields in intel_crtc_state slightly.  (Matt)

Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: ed4a6a7c ("drm/i915: Add two-stage ILK-style watermark programming (v11)")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463159442-20478-1-git-send-email-matthew.d.roper@intel.com

When we read out the watermark state from the hardware we're supposed to
transfer that into the active watermarks, but currently we fail to any
part of the active watermarks that isn't explicitly written. Let's clear
it all upfront.

Looks like this has been like this since the beginning, when I added the
readout. No idea why I didn't clear it up.

Cc: Matt Roper <matthew.d.roper@intel.com>
Fixes: 243e6a44 ("drm/i915: Init HSW watermark tracking in intel_modeset_setup_hw_state()")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463151318-14719-2-git-send-email-ville.syrjala@linux.intel.com

All the fields in CDCLK_CTL we don't program should be left at zero, so
let's just get rid of the RMW.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-14-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

BXT could change the CD2X divider synchronized with a single pipe.
So assuming the DE PLL frequency doesn't need to be changed, we could
change cdclk without shutting off the pipe (when only a single pipe is
enabled). In the meantime let's configure CDCLK_CTL for non-double
buffered CD2X update, although it shouldn't really matter as long as
the selected pipe is disabled when reprogramming the divider.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-13-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

The 'required' part of 'required_vco' should be obvious. Let's just call
it 'vco' for brevity.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-12-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Rename the generic sounding freq/frequency parameters to the cdclk
functions to 'cdclk' so that we'll know which clock we're talking about
once we have to deal with the vco frequencies as well.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-11-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

We calculate the CDCLK_CTL value from scratch so no need to attempt
some form of RMW first.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-10-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Make thins a bit easier to read by extracting the SKL DPLL0
disable into separate functions. We already have the enable
counterpart. Down the line this will also help make the cdclk
programming on SKL, BXT, and following platforms look rather
consistent.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-9-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

We don't need any pixel clock vs. cdclk guardband since HSW. BXT still
tries to add one though. Get rid of it.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-8-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

Both SKL and BXT need to fill in the "decimal" cdclk frequency into
the CDCLK_CTL register. SKL uses a small helper to do the kHz->"decimal"
conversion, whereas BXT has it open-coded. Use the helper on BXT too.

While at it, change it to round to closest rather than down. It doesn't
actually matter with the frequencies we have to deal with, but it seems
like the right thing to do.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-7-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

BXT uses the "pch" panel fitter configuration, so we can use
ilk_max_pixel_rate() instead of intel_mode_max_pixclk() to compute the
pipe pixel rate. ilk_max_pixel_rate() will account for the pipe
scaler downscaling factor whereas intel_mode_max_pixclk() will not.

I'm pretty sure the same limitation is there on GMCH platforms, but
no one just bothered to implement the downscaling adjustment for them.
Probably should just unify the panel fitter setup more across the
platforms and use the exact same code on all platforms for this.
But in the meantime, let's at least make BXT a bit more correct.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-6-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

broxton_calc_cdclk() doesn't need dev_priv for anything, so let's not
bother passing it around.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-5-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Split the .fdi_link_train and .modeset_commit_cdclk/.modeset_calc_cdclk
into two separate if ladders. Much easier to read when you're not
confusing two totally separate subjects.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-4-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Try to reduce the amount of duplicated cdclk magic numbers by
moving the max_pixclk->cdclk conversion into a helper.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-3-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

commit 565602d7 ("drm/i915: Do not acquire crtc state to check clock during modeset, v4.")
removed the possibility that intel_mode_max_pixclk() or
ilk_max_pixel_rate() might return an error, so let's get rid of the
error checks in the callers as well.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462995892-32416-2-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

We calculate the watermark config into intel_atomic_state and then save
it into dev_priv, but never actually use it from there.  This is
left-over from some early ILK-style watermark programming designs that
got changed over time.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-18-git-send-email-matthew.d.roper@intel.com

If we can't find any valid level 0 watermark values for the requested
atomic transaction, reject the configuration before we try to start
programming the hardware.

v2:
 - Add extra debugging output when we reject level 0 watermarks so that
   we can more easily debug how/why they were rejected.

Cc: Lyude Paul <cpaul@redhat.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-17-git-send-email-matthew.d.roper@intel.com

Moving watermark calculation into the check phase will allow us to to
reject display configurations for which there are no valid watermark
values before we start trying to program the hardware (although those
tests will come in a subsequent patch).

Another advantage of moving this calculation to the check phase is that
we can calculate the watermarks in a single shot as part of the atomic
transaction.  The watermark interfaces we inherited from our legacy
modesetting days are a bit broken in the atomic design because they use
per-crtc entry points but actually re-calculate and re-program something
that is really more of a global state.  That worked okay in the legacy
modesetting world because operations only ever updated a single CRTC at
a time.  However in the atomic world, a transaction can involve multiple
CRTC's, which means we wind up computing and programming the watermarks
NxN times (where N is the number of CRTC's involved).  With this patch
we eliminate the redundant re-calculation of watermark data for atomic
states (which was the cause of the WARN_ON(!wm_changed) problems that
have plagued us for a while).

We still need to work on the 'commit' side of watermark handling so that
we aren't doing redundant NxN programming of watermarks, but that's
content for future patches.

v2:
 - Bail out of skl_write_wm_values() if the CRTC isn't active.  Now that
   we set dirty_pipes to ~0 if the active pipes change (because
   we need to deal with DDB changes), we can now wind up here for
   disabled pipes, whereas we couldn't before.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89055
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92181
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by: NDaniel Stone <daniels@collabora.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463091100-13747-1-git-send-email-matthew.d.roper@intel.com

Once we move watermark calculation to the atomic check phase, we'll want
to start rejecting display configurations that exceed out watermark
limits.  At the moment we just assume that there's always a valid set of
watermarks, even though this may not actually be true.  Let's prepare by
passing return codes up through the call stack in preparation.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-15-git-send-email-matthew.d.roper@intel.com

Slightly easier to work with than an array of bools.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-14-git-send-email-matthew.d.roper@intel.com

In an upcoming patch we'll move this calculation to the atomic 'check'
phase so that the display update can be rejected early if no valid
watermark programming is possible.

v2:
 - Drop intel_pstate_for_cstate_plane() helper and add note about how
   the code needs to evolve in the future if we start allowing more than
   one pending commit against a CRTC.  (Maarten)

v3:
 - Only have skl_compute_wm_level calculate watermarks for enabled
   planes; we can just set the other planes on a CRTC to disabled
   without having to look at the plane state.  This is important because
   despite our CRTC lock we can still have racing commits that modify
   a disabled plane's property without turning it on.  (Maarten)
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-13-git-send-email-matthew.d.roper@intel.com

In a future patch we'll want to calculate plane watermarks for in-flight
atomic state rather than the already-committed state.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-12-git-send-email-matthew.d.roper@intel.com

Now that we're properly pre-allocating the DDB during the atomic check
phase and we trust that the allocation is appropriate, let's actually
use the allocation computed and not duplicate that work during the
commit phase.

v2:
 - Significant rebasing now that we can use cached data rates and
   minimum block allocations to avoid grabbing additional plane states.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-11-git-send-email-matthew.d.roper@intel.com

Calculate the DDB blocks needed to satisfy the current atomic
transaction at atomic check time.  This is a prerequisite to calculating
SKL watermarks during the 'check' phase and rejecting any configurations
that we can't find valid watermarks for.

Due to the nature of DDB allocation, it's possible for the addition of a
new CRTC to make the watermark configuration already in use on another,
unchanged CRTC become invalid.  A change in which CRTC's are active
triggers a recompute of the entire DDB, which unfortunately means we
need to disallow any other atomic commits from racing with such an
update.  If the active CRTC's change, we need to grab the lock on all
CRTC's and run all CRTC's through their 'check' handler to recompute and
re-check their per-CRTC DDB allocations.

Note that with this patch we only compute the DDB allocation but we
don't actually use the computed values during watermark programming yet.
For ease of review/testing/bisecting, we still recompute the DDB at
watermark programming time and just WARN() if it doesn't match the
precomputed values.  A future patch will switch over to using the
precomputed values once we're sure they're being properly computed.

Another clarifying note:  DDB allocation itself shouldn't ever fail with
the algorithm we use today (i.e., we have enough DDB blocks on BXT to
support the minimum needs of the worst-case scenario of every pipe/plane
enabled at full size).  However the watermarks calculations based on the
DDB may fail and we'll be moving those to the atomic check as well in
future patches.

v2:
 - Skip DDB calculations in the rare case where our transaction doesn't
   actually touch any CRTC's at all.  Assuming at least one CRTC state
   is present in our transaction, then it means we can't race with any
   transactions that would update dev_priv->active_crtcs (which requires
   _all_ CRTC locks).

v3:
 - Also calculate DDB during initial hw readout, to prevent using
   incorrect bios values. (Maarten)

v4:
 - Use new distrust_bios_wm flag instead of skip_initial_wm (which was
   never actually set).
 - Set intel_state->active_pipe_changes instead of just realloc_pipes

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Lyude Paul <cpaul@redhat.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-10-git-send-email-matthew.d.roper@intel.com