Otherwise the hw will get confused and result in a black screen.

This regression has been most likely introduce in

commit 974b9331
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Sun Sep 5 00:44:20 2010 +0100

    drm/i915/tv: Poll for DAC state change

That commit replace the first msleep(20) with a busy-loop, but failed
to keep the 2nd msleep around. Later on we've replaced all these
msleep(20) by proper vblanks.

For reference also see the commit in xf86-video-intel:

commit 1142be53eb8d2ee8a9b60ace5d49f0ba27332275
Author: Jesse Barnes <jbarnes@hobbes.lan>
Date:   Mon Jun 9 08:52:59 2008 -0700

    Fix TV programming:  add vblank wait after TV_CTL writes

    Fxies FDO bug #14000; we need to wait for vblank after
    writing TV_CTL or following "DPMS on" calls may not actually enable the output.

v2: As suggested by Chris Wilson, add a small comment to ensure that
no one accidentally removes this vblank wait again - there really
seems to be no sane explanation for why we need it, but it is
required.

Launchpad: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/763688Reported-and-Tested-by: NRobert Lowery <rglowery@exemail.com.au>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This box has DisplayPort and VGA, but no LVDS. Product specs are at
http://h10010.www1.hp.com/wwpc/us/en/sm/WF25a/12454-12454-321959-338927-3640406-4282707.html?dnr=1
and dmidecode output can be found at http://www.getslash.de/bug_attachments/dmidecode-t5740e.txtSigned-off-by: NJan-Benedict Glaw <jbglaw@getslash.de>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have one bug report from a validation team that we get the eDP
panel sequencing still somewhat wrong: We need to enable VDD while
switching off the panel and backlight. Unfortunately that reporter
seems to have fallen off the earth :(

For another reporter this actually fixes a black panel issue because
without this the backlight/panel gets confused and doesn't light up
again.

v2: I've forgotten to remove the vdd_off call in panel_off which is
now bogus. This essentially reverts

commit 17038de5
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Apr 16 22:43:42 2012 +0100

    drm/i915/dp: Flush any outstanding work to turn the VDD off

v3: the current panel_off code forces off the vdd power, too. Which is
bogus and resulted in some funny warnings later on when we've tried to
do aux channel communications with just the vdd forced on. Fix this,
too.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46312
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43163Tested-by: NVincent Frentzel <zcecc22@gmail.com>
Cc: stable@kernel.org
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The existing assertions were written under the assumption that we wanted
to test the related PLL to a CRTC. With the split of PLL into a
separately managed entity which may be shared amongst CRTCs, we need to
pass in both the CRTC and the PLL to the assertion routine.
Occassionally, this means passing NULL for the CRTC as we wish to check
the status of the PLL irrespective of the current CRTC.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In order to avoid missed down-interrupts when coming out of RC6, it is
advised that we always reset the down-threshold upon a PM event. This is
due to that the PM unit goes through a little dance when coming out of
RC6, it first brings the GPU up at the lowest frequency then a short
time later it restores the thresholds. During that interval, the
down-interval may expire and the interrupt be suppressed.

Now aware of the dance taking place within the GPU when coming out of
RC6, one wonders what other writes need to be queued in the fifo buffer
in order to be properly sequenced; setting the RP state appears to be
one.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44006Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We've simply ignored this, which isn't too great. With this, interlaced
1080i works on my HDMI screen connected through sdvo. For no apparent
reason anything else still doesn't work as it should.

While at it, give these magic numbers in the dtd proper names and
add a comment that they match with EDID detailed timings.

v2: Actually use the right bit for interlaced.
Tested-by: NPeter Ross <pross@xvid.org>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Cc: stable@vger.kernel.org
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to remove the debugfs file. Regression introduce in

commit d5442303
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Apr 27 15:17:40 2012 +0200

    drm/i915: allow the existing error_state to be destroyed
Reported-and-Tested-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

... flaky ddc hardware can cause a spurious NAK, resulting in the i2c
core and drm edid functions not trying to retry the edid transfer.

Luckily the gmbus quiescenting also times out for these cases, so we
can get out of this mess by returning -ETIMEDOUT for this specific
case. This way we keep the fast-fail of returning -ENXIO if there is
no device present, speeding up the boot process.

This regression has been introduced in

commit e646d577
Author: Daniel Kurtz <djkurtz@chromium.org>
Date:   Fri Mar 30 19:46:38 2012 +0800

    drm/i915/intel_i2c: always wait for IDLE before clearing NAK

v2: Return -ETIMEDOUT for this case and keep the -ENXIO for real NAKs,
suggested by Daniel Kurtz.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49518Reported-and-Tested-by: NJulian Simioni <julian.simioni@gmail.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Merge tag 'drm-intel-next-2012-05-20' of git://people.freedesktop.org/~danvet/drm-intel into drm-core-next

Daniel wrote:

The last pull I'd like to squeeze into 3.5, safe for the hsw stuff mostly
bugfixes:
- last few patches for basic hsw enabling (Eugeni, infoframe support by
 Paulo)
- Fix up infoframe support, we've hopefully squashed all the cargo-culting
 in there (Paulo). Among all the issues, this finally fixes some of the
 infoframe regressions seen on g4x and snb systems.
- Fixup sdvo infoframe support, this fixes a regression from 2.6.37.
- Correctly enable semaphores on snb, we've enabled it already for 3.5,
 but the dmar check was slightly wrong.
- gen6 irq fixlets from Chris.
- disable gmbus on i830, the hw seems to be simply broken.
- fix up the pch pll fallout (Chris & me).
- for_each_ring macro from Chris - I've figured I'll merge this now to
 avoid backport pain.
- complain when the rps state isn't what we expect (Chris). Note that this
 is shockingly easy to hit and hence pretty much will cause a regression
 report. But it only tells us that the gpu turbo state got out of whack,
 a problem we know off since a long time (it cause the gpu to get stuck a
 a fixed frequency, usually the lowest one). Chris is working on a fix,
 but we haven't yet found a magic formula that works perfectly (only
 patches that massively reduce the frequency of this happening).
- MAINTAINERS patch, I'm now officially the guy to beat up."

* tag 'drm-intel-next-2012-05-20' of git://people.freedesktop.org/~danvet/drm-intel: (57 commits)
  drm/i915: IBX has a fixed pch pll to pch pipe mapping
  drm/i915: implement hsw_write_infoframe
  drm/i915: small hdmi coding style cleanups
  drm/i915: fixup infoframe support for sdvo
  drm/i915: Enable the PCH PLL for all generations after link training
  drm/i915: Convert BUG_ON(!pll->active) and friends to a WARN
  drm/i915: don't clobber the pipe param in sanitize_modesetting
  drm/i915: disable gmbus on i830
  drm/i915: Replace the feature tests for BLT/BSD with ring init checks
  drm/i915: Check whether the ring is initialised prior to dispatch
  drm/i915: Introduce for_each_ring() macro
  drm/i915: Assert that the transcoder is indeed off before modifying it
  drm/i915: hook Haswell devices in place
  drm/i915: prepare HDMI link for Haswell
  drm/i915: move HDMI structs to shared location
  drm/i915: add WR PLL programming table
  drm/i915: add support for DDI-controlled digital outputs
  drm/i915: detect digital outputs on Haswell
  drm/i915: program iCLKIP on Lynx Point
  drm/i915: program WM_LINETIME on Haswell
  ...

This should fix breakage introduced in

commit ee7b9f93
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Apr 20 17:11:53 2012 +0100

    drm/i915: manage PCH PLLs separately from pipes

v2: Add a DRM_DEBUG_KMS message to explain why a given pll was
selected, suggested by Chris Wilson.

v3: Actually run git add.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49712Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Both the control and data registers are completely different now.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

- Changed the coding style of auxiliary infoframe functions to make
  them smaller
- Fixed the column alignment of some function definitions
- Remove definition of "struct drm_crtc" in some places as they're
  used only to retrieve "struct intel_crtc"
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

At least the worst offenders:
- SDVO specifies that the encoder should compute the ecc. Testing also
  shows that we must not send the ecc field, so copy the dip_infoframe
  struct to a temporay place and avoid the ecc field. This way the avi
  infoframe is exactly 17 bytes long, which agrees with what the spec
  mandates as a minimal storage capacity (with the ecc field it would
  be 18 bytes).
- Only 17 when sending the avi infoframe. The SDVO spec explicitly
  says that sending more data than what the device announces results
  in undefined behaviour.
- Add __attribute__((packed)) to the avi and spd infoframes, for
  otherwise they're wrongly aligned. Noticed because the avi infoframe
  ended up being 18 bytes large instead of 17. We haven't noticed this
  yet because we don't use the uint16_t fields yet (which are the only
  ones that would be wrongly aligned).

This regression has been introduce by

3c17fe4b is the first bad commit
commit 3c17fe4b
Author: David Härdeman <david@hardeman.nu>
Date:   Fri Sep 24 21:44:32 2010 +0200

    i915: enable AVI infoframe for intel_hdmi.c [v4]

Patch tested on my g33 with a sdvo hdmi adaptor.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=25732
Tested-by: Peter Ross <pross@xvid.org> (G35 SDVO-HDMI)
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Reported-by: NJiri Slaby <jslaby@suse.cz>
Reported-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Hidden away within one chipset specific path was the necessary logic to
turn on the PLL. This needs to be done everywhere in order for us to
drive any display! As such as soon as we tested on a non-CougarPoint
chipset, we failed to bring up any DisplayPorts and generated a nice set
of assertion failures in the process. At least one part of our logic is
working, the part that assumes that we have no idea what we are doing.

Reported-by: guang.a.yang@intel.com
References: https://bugs.freedesktop.org/show_bug.cgi?id=49712Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Turn a fatal lockup into a merely blank display with lots of shouty
messages.

v2: Whilst in the area, convert the other BUG_ON into less fatal errors.
In particular, note that we may be called on a PCH platform not using
PLLs, such as Haswell, and so we do not always want to BUG_ON(!pll)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

... we need it later on in the function to clean up pipe <-> plane
associations. This regression has been introduced in

commit f47166d2
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Mar 22 15:00:50 2012 +0000

    drm/i915: Sanitize BIOS debugging bits from PIPECONF

Spotted by staring at debug output of an (as it turns out) totally
unrelated bug.

v2: I've totally failed to do the s/pipe/i/ correctly, spotted by
Chris Wilson.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Cc: stable@kernel.org (the regression was Cc: stable, too)
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The hw just returns garbage.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49838Reported-and-tested-by: NVladyslav <DFEW.Entwickler@googlemail.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When userspace asks whether the driver supports the BLT or BSD rings for
this chip, simply report whether those particular rings are initialised

v2: Use intel_ring_initialized()
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Rather than use the magic feature tests HAS_BLT/HAS_BSD just check
whether the ring we are about to dispatch the execbuffer on is
initialised.

v2: Use intel_ring_initialized()
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In many places we wish to iterate over the rings associated with the
GPU, so refactor them to use a common macro.

Along the way, there are a few code removals that should be side-effect
free and some rearrangement which should only have a cosmetic impact,
such as error-state.

Note that this slightly changes the semantics in the hangcheck code:
We now always cycle through all enabled rings instead of
short-circuiting the logic.

v2: Pull in a couple of suggestions from Ben and Daniel for
intel_ring_initialized() and not removing the warning (just moving them
to a new home, closer to the error).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Added note to commit message about the small behaviour
change, suggested by Ben Widawsky.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Inspired by a recent regression that seems to confuse pch transcoder
state, let's be a bit more paranoid.

References: https://bugs.freedesktop.org/show_bug.cgi?id=49712
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Pimped commit message.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch enables i915 driver to handle Haswell devices. It should go in
last, when things are working stable enough.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On Haswell, we need to properly train the DDI buffers prior to enabling
HDMI, and enable the required clocks with correct dividers for the desired
frequency.

Also, we cannot simple reuse HDMI routines from previous generations of
GPU, as most of HDMI-specific stuff is being done via the DDI port
programming instead of HDMI-specific registers.

This commit take advantage of the WR PLL clock table which is in a
separate (previous) commit to select the right divisors for each mode.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Move intel_hdmi data structure and support functions to a shared location,
to allow their usage from intel_ddi module.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This table is used for programming WR PLL clocks, used by HDMI and DVI outputs.
I split it into a separate patch to simplify the HDMI enabling patch which was
getting huge.

Note that this table is a temporary solution for WR PLL programming. It
will be reworked into a more exact algorithm at a later stage. But for
now, it provides the most accurate clock setting solution, so we use it
here.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Those are driven by DDIs on Haswell architecture, so we need to keep track
of which DDI is being used on each output.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Digital port detection on Haswell is indicated by the presence of a bit in
DDI_BUF_CTL for port A, and by a different register for ports B, C and D.
So we check for those bits during the initialization time and let the hdmi
function know about those.

Note that this bit does not indicates whether the output is DP or HDMI.
However, the DDI buffers can be programmed in a way that is shared between
DP/HDMI and FDI/HDMI except for PORT E.

So for now, we detect those digital outputs as being HDMI, but proper DP
support is still pending.

Note that DDI A can only drive eDP, so we do not handle it here for hdmi
initialization.

v2: simplify Haswell handling logic

v3: use generic function for handling digital outputs.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The iCLKIP clock is used to drive the VGA pixel clock on the PCH. In order
to do so, it must be programmed to properly do the clock ticks according
to the divisor, phase direction, phase increments and a special auxiliary
divisor for 20MHz clock.

v2: calculate divisor values directly instead of relying on a table.

v3: merged a fix from Ben to properly check for invalid divider values.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The line time can be programmed according to the number of horizontal
pixels vs effective pixel rate ratio.

v2: improve comment as per Chris Wilson suggestion

v3: incorporate latest changes in specs.

v4: move into wm update routine, also mention that the same routine can
program IPS watermarks. We do not have their enablement code yet, nor
handle the required clock settings at the moment, so this patch won't
program those values for now.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For now, we simple reuse the Ivy Bridge routines here.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Starting with Haswell, DDI ports can work in FDI mode to support
connectivity with the outputs located on the PCH.

This commit adds support for such connections in the intel_ddi module, and
provides Haswell-specific functionality to make it work.

v2: simplify the commit as per Daniel Vetter suggestion.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

DDI is introduced starting with Haswell GPU generation. So to simplify its
management in the future, we also add intel_ddi.c to hold all the
DDI-related items.

Buffer translations for DDI links must be initialized prior to enablement.
For FDI and DP, first 9 pairs of values are used to select the connection
parameters. HDMI uses the last pair of values and ignores the first 9
pairs. So we program HDMI values in both cases, which allows HDMI to work
over both FDI and DP-friendly buffers.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On Haswell, only one pipe can work in FDI mode, so this patch prevents
messing with wrong registers when FDI is being used by non-first pipe. And
to prevent this, we also specify that the VGA can only be used on pipe 0
for now in the crtc_mask value.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Prevent bogus asserts on DDI-related paths.

Longer explanation from Eugeni by mail:

"For the asserts there are 3 paths where we hit them:
- in assert_fdi_tx (we don't have the FDI_TX_CTL anymore, backup plan
  DDI_FUNC_CTL is used instead)
- in assert_fdi_tx_pll_enabled (we have the combination of iCLKIP and
  DDI_FUNC_CTL, plus PORT_CLK_SEL and PIPE_CLK_SEL now to make things
  work). We could use an assert here indeed - if we configure port to
  use one clock, and pipe to use another, everything hangs. Right now,
  we configure all of them in one place only; but yes, when DP code
  lands it will get more funky.
- and in ironlake_fdi_pll_enable. I reuse part of this function (to
  configure the TU sizes), but as in the 1st case, FDI_TX_CTL is gone
  so I just ignore it here."
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
[danvet: Pasted Eugeni's explanation into the commit message.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Avoid bogus asserts and PCH PLL accesses on Lynx Point.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This attempts to enable all the available power wells during the
initialization.

Those power wells can be enabled in parallel or on-demand, and disabled
when no longer needed, but this is out of scope of this initial
enablement. Proper tracking of who uses which power well will require
a considerable rework of our display handling, so we just leave them all
enabled when the driver is loaded for now.

v2: use more generic and future-proof code
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On Haswell, the recommended PCH-connected output is the one driven by DDI
E in FDI mode, used for VGA connection. All the others are handled by the
CPU.

Note that this does not accounts for Haswell/PPT combination yet, so if we
encounter such combination an error message is thrown to indicate that
things could go wrong.

v2: improve non-LPT detection warning per Daniel Vetter's suggestion.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This should be already configured when FDI auto-negotiation is done.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>