intel_ddi.c:955:41: sparse: constant 8400000000 is so big it is long
intel_ddi.c:955:53: sparse: constant 9000000000 is so big it is long
intel_ddi.c:955:65: sparse: constant 9600000000 is so big it is long
intel_ddi.c:1028:23: sparse: constant 9600000000 is so big it is long
intel_ddi.c:1031:23: sparse: constant 9000000000 is so big it is long
intel_ddi.c:1034:23: sparse: constant 8400000000 is so big it is long
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Given the history, there's some chance we'll keep the same WM code for a
bit (previously, we were able to reuse the same WM code from ILK to BDW,
so that sounds like a fair assumption).
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Write and reads following the block changed use engine specific use counters
and unless that is matched here force wake use counting goes bad. Same
force wake is attempted to be taken twice which leads to at least time outs.

NOTE: Depending on feedback from hardware designers it may not be necessary
to grab force wakes on Gen9 here. But for Gen8 it is needed due to a race
between RC6 and ELSP writes.

v2: Added blitter force wake engine and made more future proof.
    Added commit note.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ville found out that the DATA1 register exists since SNB with some
scarce apparitions in the specs throughout the times. In his own words:

  Also according to Bspec the mailbox data1 register already existed
  since snb.  The hsw cdclk change sequence also mentions that it should
  be set to 0, but eg. the bdw IPS sequence doesn't mention it. I guess
  in theory some pcode command might cause it to be clobbered, so I'm
  thinking we should just explicitly set it to 0 for all platforms in
  the pcode read/write functions
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The LRC increased in size on gen9. Make sure we return the right
size in get_lr_context_size()

v2. Corrected the size, should be 22 pages. I unintentionally mailed out
a test patch w/ size equaling 23 pages.
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NMichael H. Nguyen <michael.h.nguyen@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Use the new AUX port irq bits where needed.

v2: Rebase on top of upstream changes
v3: Rebase on top of Oscar change to write IIR as soon as possible (Damien)
v4: Rebase on top of the for_each_pipe() change adding dev_priv as first
    argument (Damien)
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This moved around on SKL, so we need to make sure we read/write the
correct regs.

v2: fixup WIN_POS offsets (Paulo)
    zero out WIN_POS reg at disable time (Paulo)
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuougseek.org>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A few bits have changed in MI_DISPLAY_FLIP to accomodate the new planes.
DE_RRMR seems to have kept its plane flip bits backward compatible.

v2: Rebase on top of nightly
v3: Rebase on top of nightly (minor conflict in i915_reg.h)
v4: Remove code that is now part of intel_crtc_page_flip()
    Don't use BUG() in default:
    Use intel_crtc->unpin_work->gtt_offset
    (Paulo)
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The eDP WA to stop link train based on port type is for HSW/BDW, not
required for SKL+.
Suggested by Satheesh

v2: Simplified the check befoe stop_link_train. Suggested by Satheesh.

v3: stop_link_train need not be called from intel_enable_ddi for gen >= 9
Suggested-by: NSatheeshakrishna M <satheeshakrishna.m@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NSatheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: NVandana Kannan <vandana.kannan@intel.com>
Cc: Satheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: rebase on top of the hw state flattening.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch implements SKL DPLL programming that includes:
        - DPLL allocation
        - wide range PLL calculation and programming
        - DP link rate programming
        - DDI to DPLL mapping

v2: Incorporated following changes
        - Added vfunc for function required outside
        - Fixed multiple comments in WRPLL calculation

v3: - Fix the DCO computation
    - Move the initialization up to not clobber the computed values
    - Use the correct macro for DP link rate programming.
    - Use wait_for() to wait for the PLL locked bit

v4: Rebase on top of nigthly (Damien)

v5: A few code cleanups in the WRPLL computation (Damien)
    - Use uint32_t when possible
    - Use abs_diff() in the WRPLL computation
    - Make the 64bits divisions use div64_u64()
    - Fix typo in dco_central_feq_deviation (freq)
    - Replace the chain of breaks with a goto

v6: Port of the patch to work on top of the shared DPLLs (Damien)
v7: Don't try to handle eDP in ddi_pll_select() (Damien)
v8: Modified as per review comments from Paulo (Satheesh)
v9: Rebase on top of Ander's clock computation staging work for atomic (Damien)
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v3)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Skylake deprecates the usage of PORT_CLK_SEL and we are advised to use
the new DPLL_CRTL2 for the DDI->PLL mapping.

v2: Modified as per review comments
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NSatheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On skylake, DPLL 1, 2 and 3 can be used for DP and HDMI. The shared dpll
framework allows us to share those DPLLs among DDIs when possible.

The most tricky part is to provide a DPLL state that can be easily
compared. DPLL_CRTL1 is shared by all the DPLLs, 6 bits each. The
per-dpll crtl1 field of the hw state is then normalized to be the same
value if 2 DPLLs do indeed have identical values for those 6 bits.

v2: Port the code to the shared DPLL infrastructure (Damien)

v3: Rebase on top of Ander's clock computation staging work for atomic (Damien)

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v2)
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v1)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Modify the implementation to query DPLL attached to a SKL port.

v2: Rebase on top of the run-time PM on DPMS series (Damien)

v3: Modified as per review comments from Paulo
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NSatheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Fixup compilation due to the removal of the intel_ddi_dpll_id enum.
And add a fixme about the abuse of pipe_config here.

v3: Rebase on top of the hsw_ddi_clock_get() rename (Damien)

v4: Modified as per review comments from Paulo
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v3)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v2)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Determine programmed cd clock for SKL.

v2: Fix the LCPLL1 enable warning logic

v3: Rebase over the hsw pll rework.

v4: Rebase on top of the per-platform split (Damien)

v5: Modified as per review comments from Paulo
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NSatheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Adding structure/enum for SKL clocking implementation.

v2: Addressed Damien's comment
	- Removed internal structure from this header file

v3: Stove this into the generic intel_dpll_id enum and give them the established
DPLL_ID_ prefixes. (Daniel)

v4: - We'll only try to share DPLL1/2/3, leaving DPLL0 to eDP
    - Use SKL in the skylake shared DPLL names
    - Re-add the skl_dpll enum
    (Damien)

v5: Remove SKL_DPLL_NONE (Daniel)

v6: Modified as per review comments from Paulo
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v2)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v4,v5)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v3)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch defines the necessary SKL registers for implementing the
new clocking mechanism.

v2: Addressed review comments by Damien
	- Added code comment
	- Introduced enum for WRPLL values

v3: Rebase on top of nightly (minor conflict in i915_reg.h)

v4: Use 0x, not 0X (Ville)

v5: Modified as per review comments from Paulo
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v2)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v3,v4)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some machines may have a broken VBT or no VBT at all, but we still want
to use SSC there.  So check for it and keep it enabled if we see it
already on.  Based on an earlier fix from Kristian.

v2: honor modparam if set too (Daniel)
    read out at init time and store for panel_use_ssc() use (Jesse)
v3: trust BIOS configuration over VBT like we do for DP (Jani)
Reported-by: NKristian Høgsberg <hoegsberg@gmail.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This has been invalidated in

commit 24f3a8cf
Author: Akash Goel <akash.goel@intel.com>
Date:   Tue Jun 17 10:59:42 2014 +0530

    drm/i915: Added write-enable pte bit supportt

But despite that it's in the diff context no one noticed :(

Cc: Akash Goel <akash.goel@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Use the same conditions, group by features, add comments.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is not used within the driver, and merely saving/restoring these
registers isn't going to do any good anyway. In fact, it's possible it's
actively harmful. Any code enabling the feature should handle this
completely in the regular platform specific enable/disable backlight
functions.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

AFAICT i9xx_pfit_disable() on the GMCH display crtc disable path in
i9xx_crtc_disable() will always disable the panel fitter by writing 0 to
PFIT_CONTROL. The register save will always save/restore 0. Also we
completely recompue both in intel_gmch_panel_fitting so there's no way
we depend upon leftover bits.

Move the PFIT_CONTROL and PFIT_PGM_RATIOS save/restore to UMS
code. While at it, save/restore them both under the same conditions.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Make it a bit clearer that we nowhere depend upon these
bits.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The block was added for spin_lock_irqsave flags, but since the locking
was converted to spin_lock_irq variant, the block is no longer needed.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since RSTDBYCTL is only saved on non-KMS path in within i915_save_state,
move the restore in i915_restore_state for symmetry.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Don't save the panel power sequencer register on vlv/chv for two simple
reasons. First, these are the wrong registers to save to begin
with. Second, they are not restored anyway.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As per latest pm guide, we need to do this also on
past hsw.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Following the legacy ring submission example, update the
ring->init_context() hook to support the execlist submission mode.

v2: update to use the new workaround macros and cleanup unused code.
This takes care of both bdw and chv workarounds.

v2.1: Add missing call to init_context() during deferred context creation.

v3: Split init_context (emit) in legacy/lrc modes. For lrc, get the ringbuf
from the context (Mika/Daniel).

v4: Merge init_context interfaces back, the legacy mode only needs the ring,
but the lrc mode needs the ring and context (Mika).

Issue: VIZ-4092
Issue: GMIN-3475
Change-Id: Ie3d093b2542ab0e2a44b90460533e2f979788d6c
Cc: Deepak S <deepak.s@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
[danvet: Align function paramater lists properly.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When reading a CCK register we should obviously read it from CCK not
Punit. This problem has been present ever since this of code was
introduced in

 commit 67c3bf6f
 Author: Deepak S <deepak.s@linux.intel.com>
 Date:   Thu Jul 10 13:16:24 2014 +0530

    drm/i915: populate mem_freq/cz_clock for chv

The problem was raised during review by Mika [1] but somehow slipped
through the cracks, and the patch got applied with the problem unfixed.

[1] http://lists.freedesktop.org/archives/intel-gfx/2014-July/048937.html

Cc: Deepak S <deepak.s@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDeepak S <deepak.s@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The predicate source registers are needed to implement conditional
rendering without stalling. The two source registers are used to load
the previous values of the PS_DEPTH_COUNT register saved from
PIPE_CONTROL commands. These can then be compared and used to set the
predicate enable bit via the MI_PREDICATE command.

The command parser version number is increased to 2 to make it easier
to detect the new functionality in user space.
Signed-off-by: NNeil Roberts <neil@linux.intel.com>
Reviewed-by: Brad Volkin <bradley.d.volkin@intel.com> (v1)
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This only affects the fastboot path as-is.  In that case, we simply need
to make sure that we update the pipe size at the first mode set.  Rather
than putting it off until we decide to flip (if indeed we do end up
flipping), update the pipe size as appropriate a bit earlier in the
set_config call.

This sets us up for better pipe tracking in later patches.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If these change (e.g. after a modeset following a fastboot), we need to
do a full mode set.

v2:
  - put under pipe_config check so we don't deref a null state (Jesse)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is useful for checking things later.

v2:
  - fix hsw infoframe enabled check (Ander)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
[danvet: Add the missing PIPE_CONF_CHECK_I(has_infoframe); line to the
hw state cross-checker.]
[danet: Squash in fixup from Jesse to correctly compute has_infoframe
in the hdmi compute_config function.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This will allow us to consult more info before deciding whether to flip
or do a full mode set.

v2:
  - don't use uninitialized or incorrect pipe masks in set_config
    failure path (Ander)
v3:
  - fixup for pipe_config changes in compute_config (Jesse)
v4:
  - drop spurious hunk in force restore path (Ander)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This allows us to calculate the full pipe config before we do any mode
setting work.

v2:
  - clarify comments about global vs. per-crtc mode set (Ander)
  - clean up unnecessary pipe_config = NULL setting (Ander)
v3:
  - fix pipe_config handling (alloc in compute_config, free in set_mode) (Jesse)
  - fix arg order in set_mode (Jesse)
  - fix failure path of set_config (Ander)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that the backlight device no longer gets registered too early we
should be able to drop most of the INVALID_PIPE checks from the backlight
code.

The only exceptio is the opregion stuff where we may (in theory at
least) get a request from the BIOS already during driver init as soon as
the backlight setup has been done. In which case we can still get the
INVALID_PIPE from intel_get_pipe_from_connector(). So leave that check
in place, and add a comment explaining why.

For the rest, if we still manage to get here with INVALID_PIPE on
VLV/CHV we will now get a WARN from the lower level functions and
can then actually investigate further.

v2: Leave the check in the BIOS related code (Jani)

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently we register the backlight device as soon as we register the
connector. That means we can get backlight requests from userspace
already before reading out the current modeset hardware state.

That means we don't yet know the current crtc->encoder->connector mapping,
which causes problems for VLV/CHV which need to know the current pipe in
order to figure out which BLC registers to poke. Currently we just
ignore such requests fairly deep in the backlight code which means the
backlight device brightness property will get out of sync with our
backlight.level and the actual hardware state.

Fix the problem by delaying the backlight device registration until the
entire modeset init has been performed. And we also move the
backlight unregisteration to happen as the first thing during the
modeset cleanup so that we also won't be bothered with userspace
backlight requested during teardown.

This is a real world problem on machines using systemd, because systemd,
for some reason, wants to restore the backlight to the level it used last
time. And that happens as soon as it sees the backlight device appearing
in the system. Sometimes the userspace access makes it through before
the modeset init, sometimes not.

v2: Do not lie to the user in the debug prints (Jani)
    Include connector name in the prints (Jani)
    Fix a typo in the commit message (Jani)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On VLV/CHV both pipes A and B have their own backlight control
registers. In order to correctly read out the current hardware state at
init we need to know which pipe is driving the eDP port. Pass that
information down from the eDP init code into the backlight code.

To determine the correct pipe we first look at which pipe is currently
configured in the port control register, if that look invalid we look
at which pipe's PPS is currently controlling the port, and if that
too looks invalid we just assume pipe A.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the connector would have an encoder but the encoder didn't have a
crtc we might dereference a NULL crtc here. I suppose that should never
happen due to intel_sanitize_encoder(), but let's be a bit paranoid
print a warning if we ever hit this and return INVALID_PIPE to the
caller.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On VLV/CHV when the display is off, we can't read out the current
backlight level from the hardware since we have no pipe to do so.
Currently we end up reading a bigus register due to passing
INVALID_PIPE to VLV_BLC_PWM_CTL().

Skip the entire .get_backlight() call if the backlight isn't enabled
according to backlight.enabled.

This problem can be reproduced simply by reading the backlight device
actual_brightness file while the display is off.

Cc: Jani Nikula <jani.nikula@intel.com>
Suggested-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>