This reverts commit 03752f5b.

This revert requires a bit of explanation on how I understand things
work. Internally the architects/designers decide how the stolen encoding
works. We put it in a doc. BIOS writers take these docs and implement
it. Driver writers read the doc too, and read the value left by the BIOS
writers, and then we make magic.

The failing here is that in the docs we had[1] contained two different
definitions for this register for Gen7. (We have both a PCI register,
and an MMIO, and each of these were different). At the time [2] of
03752f5b, we asked the architects what the correct value should be; but
that doesn't match the reality (BIOS) unfortunately.

So on all machines I can get my hands on, this revert is the right thing
to do. I've also worked with the product group to confirm that they
agree this revert is what we should do. People using HW made my "people"
who both write their own BIOS, and have access to our docs (Apple?).
Investigations are still ongoing about whether we need to add a list
of machines needing special handling, but this patch should be the
right thing for pretty much everyone.

[1] The docs are still wrong on this one. Now instead of two registers with
two definitions, we have one register with BOTH definitions, progress?
[2] The open source PRMs have the "wrong" definitions in chapter Volume
1 part6, section 1.1.12.

This digging was inspired by Paulo.

Cc: Paulo Zanoni <przanoni@gmail.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Augment the patch saying that it's still a bit unclear
whether there are any machines out there with "wrong" firmware and
whether we need to add a list to handle them specially.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

According to BSpec the link training sequence for eDP on HSW port-A
should be as follows:

1. link training: clock recovery
2. link training: equalization
3. link training: set idle transmission mode
4. display pipe enable
5. link training: disable (set normal mode)

Contrary to this at the moment we don't do step 3. and we do step 5.
before step 4. Fix this by setting idle transmission mode for eDP at
the end of intel_dp_complete_link_train and adding a new
intel_dp_stop_link_training function to disable link training. With
these changes we'll end up with the following functions corresponding
to the above steps:

intel_dp_start_link_train    -> step 1.
intel_dp_complete_link_train -> step 2., step 3.
intel_dp_stop_link_train     -> step 5.

For port-A we'll call intel_dp_stop_link_train only after enabling the
pipe, for everything else we'll call it right after
intel_dp_complete_link_train to preserve the current behavior.

Tested on HSW/HSW-ULT.

In v2:
- Due to a HW issue we must set idle transmission mode for port-A too
  before enabling the pipe. Thanks for Arthur Runyan for explaining
  this.
- Update the patch subject to make it clear that it's an eDP fix, DP is
  not affected.

v3:
- rename intel_dp_link_train() to intel_dp_set_link_train(), use 'val'
  instead 'l' as var name. (Paulo)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Tested-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 57c21963.

It's an ugly hack for a Haswell SDV platform where the vbt doesn't
seem to fully agree with the panel. Since it seems to cause issues on
real eDP platform let's just kill this hack again.
Reported-and-tested-by: NJosh Boyer <jwboyer@gmail.com>
References: https://lkml.org/lkml/2013/5/3/467
Cc: Paulo Zanoni <przanoni@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since we know that locking is broken in that case and it's more
important to not flood the dmesg with random gunk.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
References: http://lkml.kernel.org/r/20130502000206.GH15623@pd.tnic
Cc: stable@vger.kernel.org
Reported-and-tested-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Fix the incorrect enabled pipes mask for pipe C in the WM calculations.

Additionally, in an effort to make the code easier to understand,
populate the mask with 1 << PIPE_[ABC] instead of raw numbers.

v2: Use 1 << PIPE_[ABC] (ickle/danvet)
v3: Pass PIPE_[ABC] to g4x_compute_wm0() (ickle)
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In

commit 9e8944ab
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 15 11:32:17 2012 +0000

    drm: Introduce an iterator over holes in the drm_mm range manager

helpers and iterators for hole handling have been introduced with some
debug BUG_ONs sprinkled over. Unfortunately this broke the mm dumper
which unconditionally tried to compute the size of the very first
hole.

While at it unify the code a bit with the hole dumping in the loop.

v2: Extract a hole dump helper.
Reported-by: NChristopher Harvey <charvey@matrox.com>
Cc: Christopher Harvey <charvey@matrox.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Acked-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As we recompute the remaining timeout after waiting, there is a
potential for that timeout to be less than zero and so need sanitizing.
The timeout is always returned to userspace and validated, so we should
always perform the sanitation.

v2 [vsyrjala]: Only normalize the timespec if it's invalid
v3: Add a comment to clarify the situation and remove the now
    useless WARN_ON() (ickle)

Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When ppgtt is enabled, dev_priv->gtt.total has excluded the gtt space
occupied by ppgtt table in i915_gem_init_global_gtt() function. So the
calculation of first_pd_entry_in_global_pt doesn't need to subtract
I915_PPGTT_PD_ENTRIES again. Or else PPGTT directory table will be
destroyed by global gtt allocation.

This regression has been introduced in

commit a54c0c27
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Thu Jan 24 14:45:00 2013 -0800

    drm/i915: remove intel_gtt structure

The breakage is pretty subtile since the old gtt_total_entries
included the pde range, whereas the new on did not.

Cc: stable@vger.kernel.org
Signed-off-by: Xiong Zhang<xiong.y.zhang@intel.com>
[danvet: Add regression citation and cc: stable. Thanks to Chris for
correcting my wrong guess about which commit broke things.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit fec46b5e.

The latest version of our PM programming doc (which is WAY better than
previous versions, and thanks for that) says something along the lines
of, "On Haswell overclocking is no long achieved via mailbox registers."
Which I misinterpreted as, the driver must done something different than
it did on IVB, and SNB.

It appears I jumped the gun, and that's all false. We've gotten some
clarification, and it appears at least *reading* the overclocking
information works in exactly the same manner.

Cc: kim.l.saw-chu@intel.com
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The BIOS uses power of two values for the data/link N value.

Follow suit to make the Zotac DP to dual-HDMI dongle work.

v2: Clean up the magic numbers and defines
    Change the N clamping to be a bit easier on the eye
    Rename intel_reduce_ratio to intel_reduce_m_n_ratio

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59810Tested-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Automatic color range selection was added in

commit 55bc60db
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Thu Jan 17 16:31:29 2013 +0200

    drm/i915: Add "Automatic" mode for the "Broadcast RGB" property

but that removed the check to avoid a full modeset if the value is
unchanged. Unfortunately X sets all properties with their current
value at start-up, resulting in some ugly flickering which shouldn't
be there.

v2: Change old_range from bool to uint32_t, spotted by Ville.

v3: Actually git add everything ;-)

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

As discussed in this thread
http://lists.freedesktop.org/archives/dri-devel/2013-April/037411.html
GMBUS based DVO transmitter detection seems to be unreliable which could
result in an unusable DVO port.

The attached patch fixes this by falling back to bit banging mode for
the time DVO transmitter detection is in progress.
Signed-off-by: NDavid Müller <d.mueller@elsoft.ch>
Tested-by: NDavid Müller <d.mueller@elsoft.ch>
Cc: stable@vger.kernel.org
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>

Bits 30 and 24:0 are PBC, so don't zero them. Some of the other bits
are being zeroed, but I couldn't find a reason for this, so leave them
as they are for now to avoid regressions.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
[danvet: Delete the redudant #define that Imre spotted in his review.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Check the VBT to see if the machine has inverted FDI RX polarity on
CPT. Based on this bit, set the appropriate bit on the TRANS_CHICKEN2
registers.

This should fix some machines that were showing black screens on all
outputs.

Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=60029Signed-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>

We disable hoptplug detection when we encounter a hotplug event
storm. Still hotplug detection is required on some outputs (like
Display Port). The interrupt storm may be only temporary (on certain
Dell Laptops for instance it happens at certain charging states of
the system). Thus we enable it after a certain grace period (2 minutes).
Should the interrupt storm persist it will be detected immediately
and it will be disabled again.

v2: Reordered drm_i915_private: moved hotplug_reenable_timer to hpd state tracker.
v3: Clarified loop start value,
    Removed superfluous test for Ivybridge and Haswell,
    Restructured loop to avoid deep nesting (all suggested by Ville Syrjälä)
v4: Fixed two bugs pointed out by Jani Nikula.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch disables hotplug interrupts if an 'interrupt storm'
has been detected.
Noise on the interrupt line renders the hotplug interrupt useless:
each hotplug event causes the devices to be rescanned which will
will only increase the system load.
Thus disable the hotplug interrupts and fall back to periodic
device polling.

v2: Fixed cleanup typo.
v3: Fixed format issues, clarified a variable name,
    changed pr_warn() to DRM_INFO() as suggested by
    Jani Nikula <jani.nikula@linux.intel.com>.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

To disable previously enabled HPD IRQs we need to reset them and
set the enabled ones individually.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When an encoder is shared on several connectors there is only
one hotplug line, thus this line needs to be shared among these
connectors.
If HPD detect only works reliably on a subset of those connectors,
we want to poll the others. Thus we need to make sure that storm
detection doesn't mess up the settings for those connectors.
Therefore we store the settings in the intel_connector struct and
restore them from there.
If nothing is set but the encoder has a hpd_pin set we assume this
connector is hotplug capable.
On init/reset we make sure the polled state of the connectors
is (re)set to the default value, the HPD interrupts are marked
enabled.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
fires more than 5 times / sec).
Rationale:
Despite of the many attempts to fix the problem with noisy hotplug
interrupt lines we are still seeing systems which have issues:
Once cause of noise seems to be bad routing of the hotplug line
on the board: cross talk from other signals seems to cause erronous
hotplug interrupts. This has been documented as an erratum for the
the i945GM chipset and thus hotplug support was disabled for this
chipset model but others seem to have this problem, too.

We have seen this issue on a G35 motherboard for example:
Even different motherboards of the same model seem to behave
differently: while some only see only around 10-100 interrupts/s
others seem to see 5k or more.
We've also observed a dependency on the selected video mode.

Also on certain laptops interrupt noise seems to occur duing
battery charging when the battery is at a certain charge levels.

Thus we add a simple algorithm here that detects an 'interrupt storm'
condition.

v2: Fixed comment.
v3: Reordered drm_i915_private: moved hpd state tracking to hotplug work stuff.
v4: Followed by Jesse Barnes to use a time_..() macro.
v5: Fixed coding style as suggested by Jani Nikula.
Signed-off-by: NEgbert Eich <eich@suse.de>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
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>

We have the exact same comment inside intel_init_display. This is
a leftover from when we moved a lot of code from intel_display.c to
intel_pm.c.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Caused by me with v2 of

commit 219f4fdb
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Fri Mar 15 11:17:54 2013 -0700

    drm/i915: Introduce GEN7_FEATURES for device info

I don't have a VLV to test it with, Jesse, Ken, can one of you test?

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Haswell introduces a separate frequency domain for the ring (uncore). So
where we used to increase the CPU (IA) clock with GPU busyness, we now
need to scale the ring frequency directly instead. As the ring limits
our memory bandwidth, it is vital for performance that when the GPU is
busy, we increase the frequency of the ring to increase the available
memory bandwidth.

v2: Fix the algorithm to actually use the scaled gpu frequency for the ring.
v3: s/max_ring_freq/min_ring_freq/ as that is what it is
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Add space checkpatch complained about.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit 647416f9
Author: Kees Cook <keescook@chromium.org>
Date:   Sun Mar 10 14:10:06 2013 -0700

    drm/i915: use simple attribute in debugfs routines

made i915_next_seqno debugfs entry to crop it's output
if returned value was large enough. Using simple_attr
will limit the output to 24 bytes.

Fix is to strip out preamples on all simple attributes
that have one.

v2: Fix all simple attributes (Daniel Vetter)

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Acked-by: NKees Cook <keescook@chromium.org>
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>

Increase the number of fence registers to 32 on IVB/HSW. VLV however
only has 16 fence registers according to the docs.

Increasing the number of fences was attempted before [1], but there was
some uncertainty about the maximum CPU fence number for FBC. Since then
BSpec has been updated to state that there are in fact 32 fence registers,
and the CPU fence number field in the SNB_DPFC_CTL_SA register is 5 bits,
and the CPU fence number field in the ILK_DPFC_CONTROL register must be
zero. So now it all makes sense.

[1] http://lists.freedesktop.org/archives/intel-gfx/2011-October/012865.html

v2: Include some background information based on the previous attempt
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit 4f9b2fe0441d4bdf5666a306156b5d6755de2584
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Fri Apr 5 14:29:22 2013 -0700

    drm/i915: Better overclock support

changed the sysfs read semantics for 'gt_max_freq_mhz'. By
always returning overclock max instead of stored value.

Fix this by returning the stored value. Separate sysfs entry
should be considered for overclocking max freq.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=63415
Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Looks like a some remnant from a rebase.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

BSpec contains several scattered notes which state that the maximum
fence stride was increased to 256KB on IVB.

Testing on real hardware agrees.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Our checks for an invalid fence stride forgot to guard against
zero stride on gen4+. Fix it.

v2: Avoid duplicated code (danvet)
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

IVB and HSW use different encodings for the PPGTT cacheability bits in
the GAM_ECOCHK register.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

According to BSpec GAC_ECO_BITS register exists on Gen7 platforms as
well. Configure it accordingly.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>