An HPD interrupt may fire while we are in a function that changes
the PORT_HOTPLUG_EN register - especially when an HPD interrupt
storm occurs.
Since the interrupt handler changes the enabled HPD lines when it
detects such a storm the read-modify-write cycles may interfere.
To avoid this, shiled the rmw cycles with IRQ save spinlocks.

Changes since v1:
- Implement a function which takes care of accessing PORT_HOTPLUG_EN.
Signed-off-by: NEgbert Eich <eich@suse.de>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It would be initialized just moments later by i915_init_vm.

Rearrange the code such that i915_init_vm() is next to its callers
inside i915_gem_gtt (and so we can make it static). After removing the
dance around the files, it is clear that we are repeating some work
inside the initializers (such as calling drm_mm_init() multiple times),
so take advantage of the refactor to also remove some redundant code and
clean up the interface.

v2: Commit msg update,
    s/i915_init_vm/i915_address_space_init, move to i915_gem_gtt.c,
    init address_space during i915_gem_setup_global_gtt for ggtt.
v3: Do not init global_link - we are adding it to vm_list moments later,
    make i915_address_space_init static, use OOP style parameter order.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NMichał Winiarski <michal.winiarski@intel.com>
Reviewed-by Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This commit is essentially a rewrite of "drm/i915: Check pixel format
for fbc" from Ville Syrjälä. The idea is the same, but the code is
different due to all the changes that happened since his original
patch. So any bugs are due to my bad rewrite.

v2:
  - Drop the alpha formats (Ville).
v3:
  - Drop the stale comment (Ville).

Testcases: igt/kms_frontbuffer_tracking/*fbc*-${format_name}-draw-*
Credits-to: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

BSpec says we shouldn't enable FBC on HSW/BDW when the pipe pixel rate
exceeds 95% of the core display clock.

v2:
  - HSW also needs the WA (Ville).
  - Add the WA name (Ville).
  - Use the current cdclk (Ville).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The FBC hardware for these platforms doesn't have access to the
bios_reserved range, so it always assumes the maximum (8mb) is used.
So avoid this range while allocating.

This solves a bunch of FIFO underruns that happen if you end up
putting the CFB in that memory range. On my machine, with 32mb of
stolen, I need a 2560x1440 mode for that.

Testcase: igt/kms_frontbuffer_tracking/fbc-* (given the right setup)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Don't allow FBC for cases where the spec says we can't FBC.

v2:
  - Just WARN_ON() the strides that should have been caught earlier
    (Daniel)
  - Make it a new function since I expect this to grow more.
v3:
  - Document which IGT test is exercised by this.
v4:
  - Implement the restrictions for gens 2-6 too (Ville).
  - Fix off-by-one mistake (Ville).

Testcase: igt/kms_frontbuffer_tracking/fbc-badstride
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It will be usefull to specify w/a that affects only SKL GT3 and GT4.
Signed-off-by: NSagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NAlex Dai <yu.dai@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Modified HAS_CSR macro defination which earlier only supported
for skl, now added support for BXT.

v1: Initial version.

v2: Instaed of skylake/broxton check added gen9 check alone based
on review comment from Sunil.

Cc: Vetter, Daniel <daniel.vetter@intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: NAnimesh Manna <animesh.manna@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Shared frontbuffer bits are causing warnings when same FB is displayed
in another plane without clearing the bits from previous plane.

v2: Removing coversion of fb bits to 64 bit as it is not needed for now. (Daniel)

Change-Id: Ic2df80747f314b82afd22f8326297c57d1e652c6
Signed-off-by: NSagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: NKumar, Mahesh <mahesh1.kumar@intel.com>
[danvet: Drop INTEL_FRONTBUFFER_SPRITE_MASK since unused.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Extend init/init_hw split to context init.
   - Move context initialisation in to i915_gem_init_hw
   - Move one off initialisation for render ring to
        i915_gem_validate_context
   - Move default context initialisation to logical_ring_init

Rename intel_lr_context_deferred_create to
intel_lr_context_deferred_alloc, to reflect reduced functionality &
alloc/init split.

This patch is intended to split out the allocation of resources &
initialisation to allow easier reuse of code for resume/gpu reset.

v2: Removed function ptr wrapping of do_switch_context (Daniel Vetter)
    Left ->init_context int intel_lr_context_deferred_alloc
    (Daniel Vetter)
    Remove unnecessary init flag & ring type test. (Daniel Vetter)
    Improve commit message (Daniel Vetter)
v3: On init/reinit, set the hw next sequence number to the sw next
    sequence number. This is set to 1 at driver load time. This prevents
    the seqno being reset on reinit (Chris Wilson)
v4: Set seqno back to ~0 - 0x1000 at start-of-day, and increment by 0x100
    on reset.
    This makes it obvious which bbs are which after a reset. (David Gordon
    & John Harrison)
    Rebase.
v5: Rebase. Fixed rebase breakage. Put context pinning in separate
    function. Removed code churn. (Thomas Daniel)
v6: Cleanup up issues introduced in v2 & v5 (Thomas Daniel)

Issue: VIZ-4798
Signed-off-by: NNick Hoath <nicholas.hoath@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Harrison <john.c.harrison@intel.com>
Cc: David Gordon <david.s.gordon@intel.com>
Cc: Thomas Daniel <thomas.daniel@intel.com>
Reviewed-by: NThomas Daniel <thomas.daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is done as a separate commit, to make it easier to revert
when things break.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Normally we determine the backlight PWM modulation frequency (which we
also use as backlight max value) from the backlight registers at module
load time, expecting the registers have been initialized by the BIOS. If
this is not the case, we fail.

The VBT contains the backlight modulation frequency in Hz. Add platform
specific functions to convert the frequency in Hz to backlight PWM
modulation frequency, and use them to initialize the backlight when the
registers are not initialized by the BIOS.

v2: Fix SPT and VLV. Thanks to Clint for the VLV code.

Cc: Clint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NClint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Make LPT:LP checks look neater by wrapping the details in a
new HAS_PCH_LPT_LP() macro.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add a common function to return "yes" or "no" string based on the
argument, and drop the local versions of it.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The driver doesn't support UMS any more, so set DRIVER_MODESET by default,
remove the legacy s/r callbacks, and rename the s/r functions to make it more clear
they're only in use by switcheroo now.

Also remove an obsolete comment about atomic. Normal updates are supported only
async updates aren't yet.

v2: Don't unconditionally set DRIVER_ATOMIC, we're not yet there.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

From B spec, DDI_E port belong to PowerWell 2, but
DDI_E share the powerwell_req/staus register bit with
DDI_A which belong to DDI_A_E_POWER_WELL.

In order to communicate with the connector on DDI-E, both
DDI_A_E_POWER_WELL and POWER_WELL_2 must be enabled.

Currently intel_dp_power_get(DDI_E) only enable
DDI_A_E_POWER_WELL, this patch will not only enable
DDI_a_E_POWER_WELL but also enable POWER_WELL_2.

This patch also fix the DDI-E hotplug function.
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

DDI-E doesn't have the correspondent GMBUS pin.

We rely on VBT to tell us which one it being used instead.

The DVI/HDMI on shared port couldn't exist.

This patch isn't tested without hardware wchich has HDMI
on DDI-E.

v2: fix trailing whitespace
v3: MISSING_CASE take place of BUG()
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This partially reverts commit 74c090b1.

The DRIVER_ATOMIC cap cannot yet be exported because i915 lacks async
support.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Store max dotclock into dev_priv structure so we are able
to filter out the modes that are not supported by our
platforms.

V2:
- limit the max dot clock frequency to max CD clock frequency
  for the gen9 and above
- limit the max dot clock frequency to 90% of the max CD clock
  frequency for the older gens
- for Cherryview the max dot clock frequency is limited to 95%
  of the max CD clock frequency
- for gen2 and gen3 the max dot clock limit is set to 90% of the
  2X max CD clock frequency

V3:
- max_dotclk variable renamed as max_dotclk_freq in i915_drv.h
- in intel_compute_max_dotclk() the rounding method changed from
  round up to round down when computing max dotclock

V4:
- Haswell and Broadwell supports now dot clocks up to max CD clock
  frequency
Signed-off-by: NMika Kahola <mika.kahola@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The current versions of these two macros don't work correctly if the
argument expression happens to contain a modulo operator (%) -- when
stringified, it gets interpreted as a printf formatting character!
With a specifically crafted parameter, this could probably cause a
kernel OOPS; consider WARN_ON(p%s) or WARN_ON(f %*pEp).

Instead, we should use an explicit "%s" format, with the stringified
expression as the coresponding literal-string argument.
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: fix one error found by checkpath.pl
v3: Add one ignored break for switch-case. DDI-E hotplug
    function doesn't work after updating drm-intel tree,
    I checked the code and found this missing which isn't
    the root cause for broke DDI-E hp.  The broken
    DDI-E hp function is fixed by "Adding DDI_E power
    well domain".
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: NTimo Aaltonen <timo.aaltonen@canonical.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

This fetches the required firmware image from the filesystem,
then loads it into the GuC's memory via a dedicated DMA engine.

This patch is derived from GuC loading work originally done by
Vinit Azad and Ben Widawsky.

v2:
    Various improvements per review comments by Chris Wilson

v3:
    Removed 'wait' parameter to intel_guc_ucode_load() as firmware
        prefetch is no longer supported in the common firmware loader,
	per Daniel Vetter's request.
    Firmware checker callback fn now returns errno rather than bool.

v4:
    Squash uC-independent code into GuC-specifc loader [Daniel Vetter]
    Don't keep the driver working (by falling back to execlist mode)
        if GuC firmware loading fails [Daniel Vetter]

v5:
    Clarify WOPCM-related #defines [Tom O'Rourke]
    Delete obsolete code no longer required with current h/w & f/w
        [Tom O'Rourke]
    Move the call to intel_guc_ucode_init() later, so that it can
        allocate GEM objects, and have it fetch the firmware; then
	intel_guc_ucode_load() doesn't need to fetch it later.
        [Daniel Vetter].

v6:
    Update comment describing intel_guc_ucode_load() [Tom O'Rourke]

Issue: VIZ-4884
Signed-off-by: NAlex Dai <yu.dai@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NTom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Similar to commit c44ef60e ("drm/i915/gtt:
Allow >= 4GB sizes for vm"), i915_gem_obj_offset and i915_gem_obj_ggtt_offset
return an unsigned long, which in only 4-bytes long in 32-bit kernels.

Change return type (and other related offset variables) to u64.

Since Global GTT is always limited to 4GB, this change would not be required
in i915_gem_obj_ggtt_offset, but this is done for consistency.

v2: Remove unnecessary offset variable in do_pin, as we already have
    vma->node.start (Chris).
    Update GGTT offset too (Tvrtko).

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise it can overflow in 48-bit mode, and cause an incorrect
exec_start.

Before commit 5f19e2bf ("drm/i915: Merged
the many do_execbuf() parameters into a structure"), it was already an u64.
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: For semaphore errors, object is mapped to GGTT and offset will not
be > 4GB, print only lower 32-bits (Akash)
v3: Print gtt_offset in groups of 32-bit (Chris)

Cc: Akash Goel <akash.goel@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Introduces the Page Map Level 4 (PML4), ie. the new top level structure
of the page tables.

To facilitate testing, 48b mode will be available on Broadwell and
GEN9+, when i915.enable_ppgtt = 3.

v2: Remove unnecessary CONFIG_X86_64 checks, ppgtt code is already
32/64-bit safe (Chris).
v3: Add goto free_scratch in temp 48-bit mode init code (Akash).
v4: kfree the pdp until the 4lvl alloc/free patch (Akash).
v5: Postpone 48-bit code in sanitize_enable_ppgtt (Akash).
v6: Keep _insert_pte_entries changes outside this patch (Akash).

Cc: Akash Goel <akash.goel@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

An OEM may request increased I_boost beyond the recommended values
by specifying an I_boost value to be applied to all swing entries for
a port. These override values are specified in VBT.

v2: rebase and remove unused iboost_bit variable

Issue: VIZ-5676
Signed-off-by: NAntti Koskipaa <antti.koskipaa@linux.intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The IOMMU for Intel graphics has historically had many issues resulting
in random GPU hangs. Lets include its status when capturing the GPU hang
error state for post-mortem analysis.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There is no correspondent Aux channel for DDI-E.

So we need to rely on VBT to let us know witch one
is being used instead.

v2: Removing some trailing spaces and giving proper
credit to Xiong that added a nice way to avoid port
conflicts by setting supports_dp = 0 when using
equivalent aux for DDI-E.

Credits-to: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NXiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Instead of our own duplicated one. This fixes a bug in the driver
unload code if DRM_FBDEV_EMULATION=n but DRM_I915_FBDEV=y because we
try to unregister the nonexistent fbdev drm_framebuffer.

Cc: Archit Taneja <architt@codeaurora.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch contains the changes to remove the byte
swapping logic introduced with old dmc firmware.
While debugging PC10 entry issue for skylake found
with latest dmc firmware version 1.18 without byte
swapping dmc is working fine and able to enter PC10.

Note that apparently this was changed with dmc version 1.0 and earlier
ones indeed are byteswapped like this ...

v1: Initial version.

v2: Corrected firmware size during memcpy(). (Suggested by Sunil)

Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: NAnimesh Manna <animesh.manna@intel.com>
Signed-off-by: NVathsala Nagaraju <vathsala.nagaraju@intel.com>
Reviewed-by: NA.Sunil Kamath <sunil.kamath@intel.com>
[danvet: Add note that this only holds for released dmc firmware.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

First, an introduction. We currently have two types of GTT mmaps: the
"normal" old mmap, and the WC mmap. For frontbuffer-related features
that have automatic hardware tracking, only the non-WC mmap writes are
detected by the hardware. Since inside the Kernel both are treated as
ORIGIN_GTT, any features ignoring ORIGIN_GTT because of the hardware
tracking are destined to fail.

One of the special rules defined for the WC mmaps is that the user
should call the dirtyfb IOCTL after he is done using the pointers, so
that results in an intel_fb_obj_flush() call. The problem is that the
dirtyfb is passing ORIGIN_GTT, so it is being ignored by FBC - even
though the hardware tracking is not detecing the WC mmap operations.
So in order to fix that without having to give up the automatic
hardware tracking for GTT mmaps we transform the flush operation from
dirtyfb into a special operation: ORIGIN_DIRTYFB.

This commit fixes all the kms_frontbuffer_tracking subtests that
contain "fbc" and "mmap-wc" in their names and are currently failing
(for a total of 16 subtests).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since we may conceivably encounter situations where the upper part of the
64bit register changes between reads, for example when a timestamp
counter overflows, change the WARN into a retry loop.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Remove the leftovers, yay!

AGP for i915 kms died long ago with

commit 3bb6ce66
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Nov 13 22:14:16 2013 +0100

    drm/i915: Kill legeacy AGP for gen3 kms

and with ums now gone to there's really no users any more.

Note that device_is_agp is only called when DRIVER_USE_AGP is set and
since we've unconditionally cleared that since a while there are
really no users left for i915_driver_device_is_agp.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

It fits more with the low-level fence code, and this move leaves only
the userspace tiling ioctl handling in i915_gem_tiling.c.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

No code changes, just moving all the fence related code into a
separate file (and avoiding a bunch of forward declarations while at
it).
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Currently HPD_PORT_A is used as an alias for HPD_NONE to mean that the
given port doesn't support long/short HPD pulse detection. SDVO and CRT
ports are like this and for these ports we only want to know whether an
hot plug event was detected on the corresponding pin. Since at least on
BXT we need long/short pulse detection on PORT A as well (added by the
next patch) remove this aliasing of HPD_PORT_A/HPD_NONE and let the
return value of intel_hpd_pin_to_port() show whether long/short pulse
detection is supported on the passed in pin.

No functional change.

v2:
- rebase on top of -nightly (Daniel)
- make the check for intel_hpd_pin_to_port() return value more readable
  (Sivakumar)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NSonika Jindal <sonika.jindal@intel.com>
Reviewed-by: NSivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>