We won't be calling intel_enable_primary_plane() or
intel_disable_primary_plane() with the primary plane in the
wrong state. So remove the useless DISPLAY_PLANE_ENABLE checks.

v2: Convert the checks to WARNs instead (Daniel,Paulo)
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>

Add a mechanism by which we can evade the leading edge of vblank. This
guarantees that no two sprite register writes will straddle on either
side of the vblank start, and that means all the writes will be latched
together in one atomic operation.

We do the vblank evade by checking the scanline counter, and if it's too
close to the start of vblank (too close has been hardcoded to 100usec
for now), we will wait for the vblank start to pass. In order to
eliminate random delayes from the rest of the system, we operate with
interrupts disabled, except when waiting for the vblank obviously.

Note that we now go digging through pipe_to_crtc_mapping[] in the
vblank interrupt handler, which is a bit dangerous since we set up
interrupts before the crtcs. However in this case since it's the vblank
interrupt, we don't actually unmask it until some piece of code
requests it.

v2: preempt_check_resched() calls after local_irq_enable() (Jesse)
    Hook up the vblank irq stuff on BDW as well
v3: Pass intel_crtc instead of drm_crtc (Daniel)
    Warn if crtc.mutex isn't locked (Daniel)
    Add an explicit compiler barrier and document the barriers (Daniel)
    Note the irq vs. modeset setup madness in the commit message (Daniel)
v4: Use prepare_to_wait() & co. directly and eliminate vbl_received
v5: Refactor intel_pipe_handle_vblank() vs. drm_handle_vblank() (Chris)
    Check for min/max scanline <= 0 (Chris)
    Don't call intel_pipe_update_end() if start failed totally (Chris)
    Check that the vblank counters match on both sides of the critical
    section (Chris)
v6: Fix atomic update for interlaced modes
v7: Reorder code for better readability (Chris)
v8: Drop preempt_check_resched(). It's not available to modules
    anymore and isn't even needed unless we ourselves cause
    a wakeup needing reschedule while interrupts are off
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For a bunch of reasons we want to move away from the ->mode_set
callbacks: All hw state setup needs to move into ->enable hooks (so
that DOMS can do runtime pm) and all the configuration setup needs to
move into the compute_config functions.

To start with this make the enocer->mode_set callback optional.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The BIOS can enable a pipe but leave the primary plane disabled. This
coflicts with out current idea of primary_enabled. Read the actual
hardware plane state and set primary_enabled appropriately.

We currently assume that primary_enabled is always true when we're about
to disable a crtc. That needs to change now as the plane may not be
enabled. So replace the relevant WARNs with early returns in
intel_{enable,disable}_primary_hw_plane().

Fixes the following warning
[    3.831602] WARNING: CPU: 0 PID: 1112 at linux/drivers/gpu/drm/i915/intel_display.c:1918 intel_disable_primary_hw_plane+0xe4/0xf0 [i915]()

which got introduced here by me:
 commit e9e39655c0c30cddc3f8c09a757678a24dd36737
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Mon Apr 28 15:53:25 2014 +0300

    drm/i915: Remove useless checks from primary enable/disable
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

assert_plane_enabled() is now triggering during FDI link train because
we no longer enable planes that early.

This problem got introduced in:
 commit a5c4d7bc
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Fri Mar 7 18:32:13 2014 +0200

    drm/i915: Disable/enable planes as the first/last thing during modeset on ILK+

Just drop the assert since we shouldn't need planes for link training.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Squash in fixup for now unused plane local variable, reported
by 0-day tester.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have a struct_mutex deadlock during driver init on ILK

[   54.320273] =============================================
[   54.320371] [ INFO: possible recursive locking detected ]
[   54.320471] 3.15.0-rc2-flip_race+ #2 Not tainted
[   54.320567] ---------------------------------------------
[   54.320665] modprobe/2178 is trying to acquire lock:
[   54.320762]  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa0568b05>] intel_enable_gt_powersave+0xa5/0x9d0 [i915]
[   54.321111]
[   54.321111] but task is already holding lock:
[   54.321250]  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa05b4c2e>] intel_modeset_init_hw+0x3e/0x60 [i915]
[   54.321583]
[   54.321583] other info that might help us debug this:
[   54.321724]  Possible unsafe locking scenario:
[   54.321724]
[   54.321863]        CPU0
[   54.321954]        ----
[   54.322046]   lock(&dev->struct_mutex);
[   54.322221]   lock(&dev->struct_mutex);
[   54.322397]
[   54.322397]  *** DEADLOCK ***
[   54.322397]
[   54.322638]  May be due to missing lock nesting notation
[   54.322638]
[   54.322781] 4 locks held by modprobe/2178:
[   54.322875]  #0:  (&dev->mutex){......}, at: [<ffffffff813592eb>] __driver_attach+0x5b/0xb0
[   54.323230]  #1:  (&dev->mutex){......}, at: [<ffffffff813592f9>] __driver_attach+0x69/0xb0
[   54.323582]  #2:  (drm_global_mutex){+.+.+.}, at: [<ffffffffa04e1e0d>] drm_dev_register+0x2d/0x120 [drm]
[   54.323945]  #3:  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa05b4c2e>] intel_modeset_init_hw+0x3e/0x60 [i915]

This regression got introduced in:
 commit 586d5270b60dc1f35cc3ca982d403765bad77965
 Author: Imre Deak <imre.deak@intel.com>
 Date:   Mon Apr 14 20:24:28 2014 +0300

    drm/i915: move getting struct_mutex lower in the callstack during GPU reset

Fix the problem by not taking struct_mutex around intel_enable_gt_powersave()
in intel_modeset_init_hw() since intel_enable_gt_powersave() now grabs the
mutex itself.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to re-init sizzling on all platforms so move it to the
platform independent runtime resume callback. The ring frequency reinit
is also needed everywhere except on VLV, but gen6_update_ring_freq()
will be a noop on VLV, so we can move this function too to platform
independent code.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is needed by the next patch moving the call out from platform
specific RPM callbacks to platform independent code.

No functional change.

v2:
- patch introduce in v2 of the patchset
v3:
- simplify platform check condition (Ville)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to disable the interrupts for all platforms, so make the helpers
for this platform independent and call them from them platform
independent runtime suspend/resume callbacks.

On HSW/BDW this will move interrupt disabling/re-enabling at the
beginning/end of runtime suspend/resume respectively, but I don't see
any reason why this would cause a problem there. In any case this seems
to be the correct thing to do even on those platforms.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

While checking the error capture path I noticed that we lacked the
power domain-on check for PIPESTAT so fix this by moving that to where
the rest of pipe registers are captured.

The move also revealed that we actually don't include this register in
the error report, so fix that too.

v2:
- patch introduced in v2 of the patchset
v3:
- add back !HAS_PCH_SPLIT check (Ville)
[ Ignore my previous comment about the gen<=5 || vlv check, I realized
  that it's the same as !HAS_PCH_SPLIT. ]
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

... our current modeset code isn't good enough yet to handle this. The
scenario is:

1. BIOS sets up a cloned config with lvds+external screen on the same
pipe, e.g. pipe B.

2. We read out that state for pipe B and assign the gmch_pfit state to
it.

3. The initial modeset switches the lvds to pipe A but due to lack of
atomic modeset we don't recompute the config of pipe B.

-> both pipes now claim (in the sw pipe config structure) to use the
gmch_pfit, which just won't work.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74081Tested-by: Nmax <manikulin@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The pipe is off at that point in time, so a vblank wait is simply a
50ms wait. Caught by Jesse's verbose "make vblank wait timeouts WARN"
patch. We've probably had a few versions of this float around already.

To document assumptions put a pipe assert into the same place. And
also add a posting read.

If we ever decide to update the eld and infoframes while the pipe is
already on (e.g. for fastboot) then there's lots of work to do. So
better properly document all the hidden assumptions.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We already do this for HSW, but doing it makes sense for everything else
as well. Extend it for ILK/SNB/IVB since that's where the new watermark
code is used.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77297
[danvet: Resolve conflict since I've plucked this out of the middle of
Ville's series.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Like on hsw/bdw the pipe isn't actually running yet at this point.
This holds for both pch ports and the cpu edp port according to my
testing on ilk, snb and ivb.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77297Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is a requirement added to the spec. This patch will prevent
persistent corruption on the display.

v2: Make the wait before the vblank wait. (Art)
Try to finish early by polling the register
s/present/prevent (Chris)

Cc: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Upgrade debug output to ERROR.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

haswell_write_eld() is also used on broadwell, so let's not explicitely
mention Haswell. The rest of the function has plenty of debug output
which will print the function name, so we know where we are anyway.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Comment from Ben: It's a bit unclear whether we need this dance still
on bdw.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This always indicates a bug somewhere.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There's no point in hiding the DP M/N setup in the update_pll functions.
Just move it to the mode_set function.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Because if we keep the current code, we'll get tons of WARNs on
Broadwell, since the code is Haswell-specific.

We could have also added a Broadwell-specific code there, but it's not
really needed since we never disable LCPLL with the hotplug interrupts
still enabled. So keep the easy-and-simple-to-maintain solution until
we actually need something else.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that CRTC's have a primary plane, there's no need to track the
framebuffer in the CRTC.  Replace all references to the CRTC fb with the
primary plane's fb.

This patch was generated by the Coccinelle semantic patching tool using
the following rules:

        @@ struct drm_crtc C; @@
        -   (C).fb
        +   C.primary->fb

        @@ struct drm_crtc *C; @@
        -   (C)->fb
        +   C->primary->fb

v3: Generate patch via coccinelle.  Actual removal of crtc->fb has been
    moved to a subsequent patch.

v2: Fixup several lingering crtc->fb instances that were missed in the
    first patch iteration.  [Rob Clark]
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NRob Clark <robdclark@gmail.com>

Ensure that existing driver loops over all planes do not change behavior
when we begin adding new types of planes (primary and cursor) to the DRM
plane list in future patches.

v2: Switch to using drm_for_each_legacy_plane()

Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>

That's what the spec said! And HSW needs it through pcode (you can
only read it through MCHBAR), so create hsw_write_dcomp to abstract
the weirdness.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that PC8 is part of runtime PM, the check is useless.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just because I have a SNB machine and I can easily test it.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we don't keep the hotplug interrupts enabled anymore, we can
kill the regsave struct and just cal the normal IRQ preinstall,
postinstall and uninstall functions. This makes it easier to add
runtime PM support to non-HSW platforms.

The only downside is in case we get a request to update interrupts
while they are disabled, won't be able to update the regsave struct.
But this should never happen anyway, so we're not losing too much.

v2: - Rebase.
v3: - Rebase.
v4: - Rebase.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

These were apparently meant to protect the SAREA which only has
room for two pipes, but things clearly went a bit wonky when
first the .update_plane() hooks were split up and then pipe C
got introduced.

The checks actually protecting the SAREA live in
intel_crtc_update_sarea() these days, so the checks in the primary
plane update hooks are just historical leftovers which are to be
eliminated.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Those values are, global, only used in one function and already stored
in mode_config.cursor_{width,height}.

As a result, this initialization code has been moved from the
crtc_init() function to the global modeset_init() one.

I also renamed CURSOR_{WIDTH,HEIGHT} to MAX_CURSOR_{WIDTH,HEIGHT} to be
more accurate about what these value really are.

Cc: Sagar Kamble <sagar.a.kamble@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Instead of reading out the CD clock rate from the HW at each modeset, do
this only during driver init and resume and use the cached value during
modeset. This moves things towards a state where the sw and hw side
setup is separated. It's also needed for VLV RPM, where we don't put
device into D0 state until modeset_global_resources is called and thus
can't access any display/gfx registers.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NAntti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm we reserve/allocate and free the power context during GT power
enable/disable time. There is no need to do this, we can reserve/allocate
the buffer once during driver loading and free it during driver cleanup.
The re-reservation can also fail in case the driver previously manages to
allocate something on the given fixed address.

The buffer isn't exepected to move even if allocated by the BIOS, for
safety add an assert to check this assumption.

This also fixed a bug for Ville, where re-reserving the context failed
during a GPU reset (I assume because something else got allocated on its
fixed address).
Tested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If vsyncshift comes out as negative, add one htotal to it to get the
corresponding positive value.

This is rather theoretical as it would require a mode where the
hsync+back porch is very long and the active+front porch very short.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

PIPECONF_INTERLACE_W_FIELD_INDICATION is only meant to be used for sdvo
since it implies a slightly weird vsync shift of htotal/2. For everything
else we should use PIPECONF_INTERLACE_W_SYNC_SHIFT and let the value in
the VSYNCSHIFT register take effect.

The only exception is gen3 simply because VSYNCSHIFT didn't exist yet.
Gen2 doesn't support interlaced modes at all, so we can drop the
explicit gen2 checks.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When interlaced sdvo output is used, vsyncshift should supposedly
be (htotal-1)/2. In reality PIPECONF/TRANSCONF will override it by
using the legacy vsyncshift interlace mode which causes the hardware
to ignore the VSYNCSHIFT register.

The only odd thing here is that on PCH platforms we program the
VSYNCSHIFT on both CPU and PCH, and it's not entirely clear if both
sides have to agree on the value or not. On the CPU side there's no
way to override the value via PIPECONF anymore, so if we want to make
the CPU side agree with the PCH side, we should probably program the
approriate value into VSYNCSHIFT manually. So let's do that, but for
now leave the PCH side to still use the legacy interlace mode in
TRANSCONF.

We can also drop the gen2 check since gen2 doesn't support interlaced
modes at all.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This makes HDMI testers happier on VLV platforms.  It may be that we
need it for any non-SVO platform, but I don't have any tests to back
that up, so I'm leaving other pre-ILK platforms alone for now.

Tested-by: "Clint Taylor <clinton.a.taylor@intel.com>"
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74964Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the cursor width is changed, we may need to recompute our WM to
prevent untold flickering. We hope that the registers are flushed on the
same vblank to prevent underruns...

Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Sagar Kamble <sagar.a.kamble@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since

commit 5c673b60
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Mar 7 20:34:46 2014 +0100

    drm/i915: Don't enable display error interrupts from the start

we don't enable underrun interrupts any more at takeover time.
Unfortunately I've forgotten to also adjust the sw-side tracking.

Since the code assumes that disabled pipes have underrun reporting
enabled set the disable flag only on all pipes which are active at
takeover time. Without this underrun reporting wasn't enabled
correctly on the first modeset. Note that for fastboot this is another
piece of state that needs to be fixed up by enabling the underrung
reporting after watermarks have beend fixed up.

On ivb/hsw an additional effect of this regression was that also all
cpu crc reporting stopped working since the master error interrupt it
shared across all pipes and sources.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76150
[danvet: Augment the code comment and polish the commit message a bit,
as discussed with Jani.]
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Tested-by: Nlu hua <huax.lu@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With this patch we allow larger cursor planes of sizes 128x128
and 256x256.

v2: Added more precise check on size while setting cursor plane.

v3: Changes related to restructuring cursor size restrictions
and DRM_DEBUG usage.

v4: Indentation related changes for setting cursor control and
implementing DRM_CAP_CURSOR_WIDTH and DRM_CAP_CURSOR_HEIGHT

Testcase: igt/kms_cursor_crc
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NG, Pallavi <pallavi.g@intel.com>
Signed-off-by: NSagar Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that PC8 got much simpler, there are less things to document.
Also, runtime PM already has a nice documentation, so we don't need to
re-explain it on our driver.

v2: - Rebase.
    - Fix typo (Jesse).
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After we removed all the intermediate abstractions, we can rename
these functions to just hsw_{en,dis}able_pc8.

v2: - Rebase.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>