Alway use the alphabetical names in debug/error messages for planes,
pipes and ports, instead of using decimal numbers occasionally.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Get rid of the few remaining open coded copies of
pipe_name() and port_name().
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When adding the pipe config computation step I've accidentally moved
this a bit away. Which momentarily confused me since the pipe config
step rejected some modesetting operations I expected and so left me
looking in vain for that debug output.

v2: Move the debug output into the right function to prevent this from
happening again.

v3: Make it compile (Ville). Also reorder the patch so that the two
bugfixes are first.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The i9xx modeset sequence is currently pretty fishy, so tight it all
up with some good assert-sprinkling.

We already have good coverage on the disable side, but the enable side
is spotty (since until recently it was wrong).
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just blows through 50ms for naught, since the pipe is off.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is horrible lore and we should be able to get rid of it now
that the lvds/pfit handling code actually does the right thing.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Oops.

This regression has been introduced in

commit 5d2d38dd
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Mar 27 00:45:01 2013 +0100

    drm/i915: clean up pipe bpp confusion
Reported-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For a bunch of reason we need to more accurately track this:
- hw pipe state readout for Haswell needs the cpu transcoder.
- We need to know the right cpu transcoder in a bunch of places in
  ->disable and other modeset callbacks.

In the future we need to add hw state readout&check support, too. But
to avoid ugly merge conflicts do the rote sed job now without any
functional changes.

v2: Preserve the cpu_transcoder value when overwriting crtc->config.
Reported by Paulo.

Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
[danvet: Removed rough whitespace that Chris spotted.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We may have DDI_BUF_CTL(PORT_A) configured with 2 lanes and still not
have CRT, so just check for !IS_ULT. This problem happened on a real
machine and resulted in a very ugly dmesg.

Cc: stable@vger.kernel.org
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The recent rework of the pfit handling didn't take into account that
the panel fitter is fixed to pipe B:

commit 24a1f16d
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Fri Feb 8 16:35:37 2013 +0200

    drm/i915: disable shared panel fitter for pipe

Fix this up by properly computing the pipe the pfit is on. Also
extract the logic into its own function, add a debug assert to check
that the pipe is off (mostly just documentation) and add some debug
output.

If pipe A was disabled after pipe B was set up, the panel fitter will
be disabled. Now most userspace doesn't do modesets in this order,
which is why I couldn't ever reproduce this and why it took me so long
to figure out.

We really need hw state readout and check support for the pannel
fitter ...
Reported-by: NHans de Bruin <jmdebruin@xmsnet.nl>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Hans de Bruin <jmdebruin@xmsnet.nl>
References: http://permalink.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/19049Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Yet again our current confusion between doing the modeset globally,
but only having the new parameters for one crtc at a time.

So that intel_set_mode essentially already does a global modeset:
intel_modeset_affected_pipes compares the current state with where we
want to go to (which is carefully set up by intel_crtc_set_config) and
then goes through the modeset sequence for any crtc which needs
updating.

Now the issue is that the actual interface with the remaining code
still only works on one crtc, and so we only pass in one fb and one
mode. In intel_set_mode we also only compute one intel_crtc_config
(which should be the one for the crtc we're doing a modeset on).

The reason for that mismatch is twofold:
- We want to eventually do all modeset as global state changes, so
it's just infrastructure prep.
- But even the old semantics can change more than one crtc when you
e.g. move a connector from crtc A to crtc B, then both crtc A and B
need to be updated. Usually that means one pipe is disabled and the
other enabled. This is also the reason why the hack doesn't touch the
disable_pipes mask.

Now hilarity ensued in our kms config restore paths when we actually
try to do a modeset on all crtcs: If the first crtc should be off and
the second should be on, then the call on the first crtc will notice
that the 2nd one should be switched on and so tries to compute the
pipe_config. But due to a lack of passed-in fb (crtc 1 should be off
after all) it only results in tears.

This case is ridiculously easy to hit on gen2/3 where the lvds output
is restricted to pipe B. Note that before the pipe_config bpp rework
gen2/3 didn't care really about the fb->depth, so this is a regression
brought to light with

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

But apparently Ajax also managed to blow up pch platforms, probably
with some randomized configs, and pch platforms trip up over the lack
of an fb even in the old code. So this actually goes back to the first
introduction of the new modeset restore code in

commit 45e2b5f6
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Nov 23 18:16:34 2012 +0100

    drm/i915: force restore on lid open

Fix this mess by now by justing shunting all the cool new global
modeset logic in intel_modeset_affected_pipes.

v2: Improve commit message and clean up all the comments in
intel_modeset_affected_pipes - since the introduction of the modeset
restore code they've been a bit outdated.

Bugzill: https://bugzilla.redhat.com/show_bug.cgi?id=917725
Cc: stable@vger.kernel.org
References: http://www.mail-archive.com/stable@vger.kernel.org/msg38084.htmlTested-by: NRichard Cochran <richardcochran@gmail.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Backlight cleanup in the eDP connector destroy callback caused the
backlight device to be removed on some systems that first initialized LVDS
and then attempted to initialize eDP. Prevent multiple backlight
initializations, and ensure backlight cleanup is only done once by moving
it to modeset cleanup.

A small wrinkle is the introduced asymmetry in backlight
setup/cleanup. This could be solved by adding refcounting, but it seems
overkill considering that there should only ever be one backlight device.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55701Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Tested-by: NPeter Verthez <peter.verthez@skynet.be>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This solves some "unclaimed register" messages when booting the
machine with eDP attached.

V2: Rebase and add the comment requested by Daniel.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It returns true if we've requested to turn the power well on and it's
really on. It also returns true for all the previous gens.

For now there's just one caller, but I'm going to add more.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It will be only consistent once we've restored all the crtcs. Since a
bunch of other callers also want to just restore a single crtc, add a
boolean to disable checking only where it doesn't make sense.

Note that intel_modeset_setup_hw_state already has a call to
intel_modeset_check_state at the end, so we don't reduce the amount of
checking.

v2: Try harder not to create a big patch (Chris).

v3: Even smaller (still Chris). Also fix a trailing space.

References: https://lkml.org/lkml/2013/3/16/60
Cc: Tomas Melin <tomas.melin@iki.fi>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NTomas Melin <tomas.melin@iki.fi>
Tested-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Bspec has been been updated and dropped these two changes for non-sdv
LPT PCHs.

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>

Userspace can easily hit this and does since Ville added a new evil
igt testcase in:

commit 069e35e0fc3785faa562adcfd2dd7bbed4cb1dea
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Mon Mar 4 15:34:06 2013 +0200

    kms_flip: Add flip-vs-bad-tiling test

v2: Fix the spelling in the added comment (Chris).

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=63246Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since the ratio is different, we also need to pass in the parameters
for the reduced clock. Might or might not reduce flicker for the
auto-downclocking on lvds/eDP.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Only on IBX should we set the limiting factor to 25 unconditionally
for dual-channel mode, on CPT/PPT 25 only applies when the lvds
refclock is 100MHz.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit de13a2e3
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Thu Sep 20 18:36:05 2012 -0300

    drm/i915: extract compute_dpll from ironlake_crtc_mode_set

missed the subtle adjustment of the FP1 register. Fix this up by
passing a pointer around instead of the value.

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

GEN supports a fusing option which subtracts the PCH display (making the
CPU display also useless). In this configuration MMIO which gets decoded
to a certain range will hang the CPU.

For us, this is sort of the equivalent of having no pipes, and we can
easily modify some code to not do certain things with no pipes.

v2: Moved the num pipes check up in the call chain, and removed extra
checks noted by Daniel. For more details, see:
http://lists.freedesktop.org/archives/intel-gfx/2013-March/025746.html

v3: Drop the intel_setup_overlay check (Daniel)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

VLV has the color range selection bit in the PIPECONF register.
Configure it appropriately.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
[danvet: fixup rebase issues due to slightly different baseline.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Prep-patch to improve the bpc handling in a next patch.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Clock computations and handling are highly encoder specific, both in
the optimal clock selection and also in which clocks to use and when
sharing of clocks is possible.

So the best place to do this is somewhere in the encoders, with a
generic fallback for those encoders without special needs. To facility
this, add a pipe_config->clocks_set boolean.

This patch here is only prep work, it simply sets the computed clock
values in pipe_config->dpll, and uses that data in the hw clock
setting functions.

Haswell code isn't touched, simply because Haswell clocks work much
different and need their own infrastructure (with probably a
Haswell-specific config->ddi_clock substruct).
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now we can ditch the checks in the Haswell disable code.

v2: add support for Haswell
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to be able to read out the hw state code for a bunch
of reasons:
- Correctly disabling boot-up/resume state.
- Pure paranoia.

Since not all of the pipe configuration is e.g. relevant for
fastboot (or at least we can allow some wiggle room in some
parameters, like the clocks), we need to add a strict_checking
parameter to intel_pipe_config_compare for fastboot.

For now intel_pipe_config_compare should be fully paranoid and
check everything that the hw state readout code supports. Which
for this infrastructure code is nothing.

I've gone a bit overboard with adding 3 get_pipe_config functions:
The ilk version will differ with the next patch, so it's not too
onerous.

v2: Don't check the hw config if the pipe is off, since an enabled,
but dpms off crtc will obviously have tons of difference with the hw
state.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The only exception left is is_cpu_edp in the haswell modeset code.
We need that to assign the cpu transcoder, but we might want to
move that eventually into the encoder, too.

\o/-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need it in the fdi m_n computation, which nicely kills almost
all ugly special cases in there.

It looks like we also need this to handle 12bpc hdmi correctly.

Eventually it might be better to switch things around and put the
target clock into adjusted_mode->clock and create a new pipe_config
parameter for the port link clock.

v2: Add a massive comment in the code to explain this mess.

v3: s/dp_target_clock/pixel_target_clock in anticipation of the hdmi
use-case.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need a flag to designate dp encoders and the dp link m_n parameters
in the pipe config for that. And now that the pipe bpp computations
have been moved up and stored in the pipe config, too, we can do this
without losing our sanity.

v2: Rebased on top of Takashi Iwai's fix to (again) fix the target
clock handling for eDP. Luckily the new code is sane enough and just
does the right thing!

v3: Move ->has_dp_encoder to this patch (Jesse).
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There's a rather decent confusion going on around transcoder m_n
values. So let's clarify:
- All dp encoders need this, either on the pch transcoder if it's a
  pch port, or on the cpu transcoder/pipe if it's a cpu port.
- fdi links need to have the right m_n values for the fdi link set in
  the cpu transcoder.

To handle the pch vs transcoder stuff a bit better, extract transcoder
set_m_n helpers. To make them simpler, set intel_crtc->cpu_transcoder
als in ironlake_crtc_mode_set, so that gen5+ (where the cpu m_n
registers are all at the same offset) can use it.

Haswell modeset is decently confused about dp vs. edp vs. fdi. dp vs.
edp works exactly the same as dp (since there's no pch dp any more),
so use that as a check. And only set up the fdi m_n values if we
really have a pch encoder present (which means we have a VGA encoder).

On ilk+ we've called ironlake_set_m_n both for cpu_edp and for pch
encoders. Now that dp_set_m_n handles all dp links (thanks to the
pch encoder check), we can ditch the cpu_edp stuff from the
fdi_set_m_n function.

Since the dp_m_n values are not readily available, we need to
carefully coax the edp values out of the encoder. Hence we can't (yet)
kill this superflous complexity.

v2: Rebase on top of the ivb fdi B/C check patch - we need to properly
clear intel_crtc->fdi_lane, otherwise those checks will misfire.

v3: Rebased on top of a s/IS_HASWELL/HAS_DDI/ patch from Paulo Zanoni.

v4: Drop the addition of has_dp_encoder, it's in the wrong patch (Jesse).
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Need to make sure sprites are disabled before shutting off a pipe.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No constant alpha yet though, that needs a new ioctl and/or property to
get/set.

v2: use drm_plane_format_cpp (Ville)
    fix up vlv_disable_plane, remove IVB bits (Ville)
    remove error path rework (Ville)
    fix component order confusion (Ville)
    clean up platform init (Ville)
    use compute_offset_xtiled (Ville)
v3: fix up more format confusion (Ville)
    update to new page offset function (Ville)
v4: remove incorrect formats from framebuffer_init (Ville)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Modifying the clock sources (via the DREF control on the PCH) is a slow
multi-stage process as we need to let the clocks stabilise between each
stage. If we are not actually changing the clock sources, then we can
return early.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Appease checkpatch by deleting a space after a ~]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ville pointed out that my assumption that no unsupported pixel format
can get past the pipe config computation stage to the platform
update_plane callbacks is wrong. The reason is that this function
still checks the old fb->depth value instead of the new pixel_format.

While checking with all the other places that use this I've noticed
that intel_framebuffer_init already has all the platform checks we
need, so replace those checks with a WARN_ON.

Since fb->depth isn't set for YUV pixel formats and since we already
can't create an fb with an rgb layout not support on the running
platform I /think/ this patch doesn't fix any bug.

But it surely looks better!

v2: BGR formats are also only gen4+, so add the corresponding WARN_ON,
too (Ville).

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

We've mostly switched over to the new more flexible schema, but
there's one check left in the modeset code.

Motivated by a question from Ville whether there's really no way an
unsupported pixel_format can escape into our platform update_plane
callbacks.

v2: Ville noticed that the fb->depth check is redudant when we already
check fb->pixel_format.

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

- gen4 and earlier (save for g4x) only really have a 8bpc pipe, with
  the possibility to dither to 6bpc using the panel fitter
- g4x has hdmi, but no 12 bpc pipe ... !? Clamp hdmi accordingly.
- TV/SDVO out are the only connectors available on platforms with
  a pipe bpp != 8, add code to force the pipe to 8bpc unconditionally.

<rant>
The dither handling on gmch platforms is one giant disaster. I'm hoping
somewhat that vlv enabling will fix this up, but given that the 6bpc
handling for edp was simply added with another quick hack, I don't have
high hopes ...
</rant>

v2: Neither vlv nor g4x have 12bpc pipes. Still set pipe_bpp to 12*3,
but let the crtc code clamp things down to 10bpc on these platforms.

v3: Fix a bpc vs. bpp mixup in the gen4 and earlier pipe_bpp limiter
code.

v4: Drop the hunk in intel_hdmi.c about g4x/vlv 12bpc, it was wrong.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

- There is no 16bpc linear color format in our hw. gen4+ has a 16 bpc
  float layout, but we don't really support it.
- 10bpc is a gen4+ feature, fix up the support for it.
- Update_plane should never see a wrong fb bpp value, BUG in the
  corresponding cases.

v2: Rebase on top of Ville's plane pixel layout changes.

v3: Actually drop the old gen4 check for 10bpc planes, spotted
by Ville Syrjälä.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The old code only handled either 6bpc or 8bpc. Since it's easy to do,
reorganize the code to be a bit more generic so that it can also handle
10bpc and 12bpc. Note that we still start with 8bpc, so there's no
functional change.

Also, since we no don't need to compute the 6BPC flag in the mode_valid
callback, we can consolidate things a bit. That requires though that
the link bw computation is moved up in the compute_config callback.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The procedure has now 3 steps:

1. Compute the bpp that the plane will output, this is done in
   pipe_config_set_bpp and stored into pipe_config->pipe_bpp. Also,
   this function clamps the pipe_bpp to whatever limit the EDID of any
   connected output specifies.
2. Adjust the pipe_bpp in the encoder and crtc functions, according to
   whatever constraints there are.
3. Decide whether to use dither by comparing the stored plane bpp with
   computed pipe_bpp.

There are a few slight functional changes in this patch:
- LVDS connector are now also going through the EDID clamping. But in
  a 2nd change we now unconditionally force the lvds bpc value - this
  shouldn't matter in reality when the panel setup is consistent, but
  better safe than sorry.
- HDMI now forces the pipe_bpp to the selected value - I think that's
  what we actually want, since otherwise at least the pixelclock
  computations are wrong (I'm not sure whether the port would accept
  e.g. 10 bpc when in 12bpc mode). Contrary to the old code, we pick
  the next higher bpc value, since otherwise there's no way to make
  use of the 12 bpc mode (since the next patch will remove the 12bpc
  plane format, it doesn't exist).

Both of these changes are due to the removal of the

	pipe_bpp = min(display_bpp, plane_bpp);

statement.

Another slight change is the reworking of the dp bpc code:
- For the mode_valid callback it's sufficient to only check whether
  the mode would fit at the lowest bpc.
- The bandwidth computation code is a bit restructured: It now walks
  all available bpp values in an outer loop and the codeblock that
  computes derived values (once a good configuration is found) has been
  moved out of the for loop maze. This is prep work to allow us to
  successively fall back on bpc values, and also correctly support bpc
  values != 8 or 6.

v2: Rebased on top of Paulo Zanoni's little refactoring to use more
drm dp helper functions.

v3: Rebased on top of Jani's eDP bpp fix and Ville's limited color
range work.

v4: Remove the INTEL_MODE_DP_FORCE_6BPC #define, no longer needed.

v5: Remove intel_crtc->bpp, too, and fix up the 12bpc check in the
hdmi code. Also fixup the bpp check in intel_dp.c, it'll get reworked
in a later patch though again.

v6: Fix spelling in a comment.

v7: Debug output improvements for the bpp computation.

v8: Fixup 6bpc lvds check - dual-link and 8bpc mode are different
things!

v9: Reinstate the fix to properly ignore the firmware edp bpp ... this
was lost in a rebase.

v10: Both g4x and vlv lack 12bpc pipes, so don't enforce that we have
that. Still unsure whether this is the way to go, but at least 6bpc
for a 8bpc hdmi output seems to work.

v11: And g4x/vlv also lack 12bpc hdmi support, so only support high
depth on DP. Adjust the code.

v12: Rebased.

v13: Split out the introduction of pipe_config->dither|pipe_bpp, as
requested from Jesse Barnes.

v14: Split out the special 6BPC handling for DP, as requested by Jesse
Barnes.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We want to compute this earlier. To avoid a big complicated patch,
this patch here just does the big search&replace and still calls the
old functions at the same places.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>