This patch allows PC8+ states on Haswell. These states can only be
reached when all the display outputs are disabled, and they allow some
more power savings.

The fact that the graphics device is allowing PC8+ doesn't mean that
the machine will actually enter PC8+: all the other devices also need
to allow PC8+.

For now this option is disabled by default. You need i915.allow_pc8=1
if you want it.

This patch adds a big comment inside i915_drv.h explaining how it
works and how it tracks things. Read it.

v2: (this is not really v2, many previous versions were already sent,
     but they had different names)
    - Use the new functions to enable/disable GTIMR and GEN6_PMIMR
    - Rename almost all variables and functions to names suggested by
      Chris
    - More WARNs on the IRQ handling code
    - Also disable PC8 when there's GPU work to do (thanks to Ben for
      the help on this), so apps can run caster
    - Enable PC8 on a delayed work function that is delayed for 5
      seconds. This makes sure we only enable PC8+ if we're really
      idle
    - Make sure we're not in PC8+ when suspending
v3: - WARN if IRQs are disabled on __wait_seqno
    - Replace some DRM_ERRORs with WARNs
    - Fix calls to restore GT and PM interrupts
    - Use intel_mark_busy instead of intel_ring_advance to disable PC8
v4: - Use the force_wake, Luke!
v5: - Remove the "IIR is not zero" WARNs
    - Move the force_wake chunk to its own patch
    - Only restore what's missing from RC6, not everything
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was causing WARNs in one machine, so instead of trying to guess
exactly which hotplug bits should exist, just do the test on the
non-HPD bits. We don't care about the state of the hotplug bits, we
just care about the others, that need to be 1.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If LCPLL is disabled, there's a chance we might be in package C8 state
or deeper, and we'll get a hard hang when restoring LCPLL (also, a red
led lights up on my motherboard). So grab the force_wake, which will
get us out of RC6 and, as a consequence, out of PC8+ (since we need
RC6 to get into PC8+).

Note: Discussions with hw designers are still ongoing what exactly
goes boom here. But I think we can go ahead and just merge this little
hack for now until it's clear what we actually need.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Add small note about the current state of the discussion
around this hack.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The existing code was trying different vswing and preemphasis settings
in the wrong place, and wasn't trying them enough.  So add a loop to
walk through them, properly disabling FDI TX and RX in between if a
failure is detected.

v2: remove unneeded reg writes, add delays around bit lock checks (Jesse)
v3: fix TX and RX disable per spec (Paulo)
    fix delays per spec (Paulo)
    make RX symbol lock check match TX bit lock check (Paulo)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51983Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Whenever I need to work with the HSW_PWER_WELL_* register bits I have
to look at the documentation to find out which bit is to request the
power well and which one shows its current state. Rename the bits so I
won't need to look the docs every time.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the power well is disabled VGA is guaranteed to be disabled.

This fixes unclaimed register messages that happen on suspend/resume.

v2: Check the actual hw power well state instead of our own tracking
to make sure VGA is _really_ off (in case the BIOS/KVMr has just its
own request bit set). Requested by Ville.

Note: Ville suggested whether it wouldn't be better to just enable the
power well over a slightly longer time in our resume code, since we
already do that. I tend to agree, but there's also the modeset force
code in the lid notifier which _also_ eventually calls redisable_vga.
We shouldn't ever need this on somewhat modern hw (everything with
opregion essentially) but the code to bail out isn't there. Hence
stick with this simple approach here for now.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67517Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Summarize the discussion around the resume sequence and lid
notifier a bit.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After computing the stage changes for the set_config, record those in
the debug log.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Caught by "make W=1 drivers/gpu/drm/i915/".
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The display engine has unique coherency rules such that it requires
special handling to ensure that all writes to cursors, scanouts and
sprites are clflushed. This patch introduces the infrastructure to
simply track when an object is being accessed by the display engine.

v2: Explain the is_pin_display() magic as the sources for obj->pin_count
and their individual rules is not obvious. (Ville)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ryan noticed that on his board, HDMI was wired up to port C but not
exposed by the kernel, which had only expected DP on that port.  Fix
that up by enumerating both ports if possible.
Tested-by: N"Matsumura, Ryan" <ryan.matsumura@intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Fix up the whitespace fail. Tsk.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Caught by the dead code police!
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And also fix a small typo in the intel_encoder_dpms() comment.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Rather than open-code the teardown of a framebuffer, export the routine
from intel_display.c. This then make intel_fbdev symmetric in its use of
the common intel_framebuffer routines to initialise and clean up the
struct intel_framebuffer. (And new features need only be added in one
location!)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Userspace can pass a mode with an unspecified vsync/hsync polarity
setting. All encoders in the Intel driver take this to mean a negative
polarity setting. The HW readout/state checker code on the other hand
needs these flags to be explicitly set, otherwise the state checker will
WARN about the mismatch.

Get rid of the WARN by making the polarity setting explicit in the
adjusted mode flags based on the requested mode flags. This will keep
the existing behavior otherwise.

Note that we could guess from the other timing parameters whether the
user wanted a VESA or other standard mode and set the polarity
accordingly. This is what the NV driver does
(drivers/gpu/drm/nouveau/dispnv04/crtc.c), but I think that's not very
exact and would change the existing behavior of the Intel driver.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65442Signed-off-by: NImre Deak <imre.deak@intel.com>
Tested-by: Ncancan,feng <cancan.feng@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

VLV wants encoder enabling before the pipe is up. With the previously
rearranged VLV DP and HDMI ->pre_enable and ->enable callbacks in place,
this no longer depends on the early ->enable hook call. Move the
->enable call at the end of the sequence, similar to the crtc enable on
other platforms. This will be needed e.g. for moving the eDP backlight
enabling to the right place in the sequence, currently done too early on
VLV.

There should be no functional changes.

v2: Rebase.

v3: Explain why this is needed in the commit message (Chris).
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise we get flooded by the kernel warning us that we are doing
long sequences of IO without serialisation. For example,

 WARNING: CPU: 0 PID: 11136 at drivers/gpu/drm/i915/intel_sideband.c:40 vlv_sideband_rw+0x48/0x1ef()
 Modules linked in:
 CPU: 0 PID: 11136 Comm: kworker/u2:0 Tainted: G        W    3.11.0-rc2+ #4
 Call Trace:
  [<c2028564>] ?  warn_slowpath_common+0x63/0x78
  [<c227ad43>] ?  vlv_sideband_rw+0x48/0x1ef
  [<c20285dd>] ?  warn_slowpath_null+0xf/0x13
  [<c227ad43>] ?  vlv_sideband_rw+0x48/0x1ef
  [<c227b060>] ?  vlv_dpio_write+0x1c/0x21
  [<c2262b3b>] ?  intel_dp_set_signal_levels+0x24a/0x385
  [<c2264909>] ?  intel_dp_complete_link_train+0x25/0x1d1
  [<c2264c55>] ?  intel_dp_check_link_status+0xf7/0x106
  [<c2238ced>] ?  i915_hotplug_work_func+0x17b/0x221
  [<c203a204>] ?  process_one_work+0x12e/0x210
  [<c203a5e4>] ?  worker_thread+0x116/0x1ad
  [<c203a4ce>] ?  rescuer_thread+0x1cb/0x1cb
  [<c203d8f5>] ?  kthread+0x67/0x6c
  [<c2457ebb>] ?  ret_from_kernel_thread+0x1b/0x30
  [<c203d88e>] ?  init_completion+0x18/0x18

v2: Retire the locking in vlv_crtc_enable() and do it close to the meat.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Squash in a s/mutex_lock/mutex_unlock/ fixup spotted by the 0
day kernel build/coccinelle and reported by Dan Carpenter.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Art confirms that this should work fine.  Since most panels are 18bpp
with dithering from 24bpp, the existing code wouldn't be enabled in most
cases.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NStéphane Marchesin <marcheu@chromium.org>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In the old days of the crtc helpers we've only had the encoder and
crtc ->mode_fixup callbacks. So when the lvds connector wanted to
adjust the crtc timings it had to set a driver-private mode flag to
tell the crtc mode fixup code to not overwrite them with the generic
ones.

When converting things to the new infrastructure I've kept the entire
logic and only moved the flag to pipe_config->timings_set. But this
logic is pretty tricky and already caused regressions:

commit 21d8a475
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Jul 12 08:07:30 2013 +0200

    drm/i915: fix pfit regression for non-autoscaled resolutions

So take advantage of the flexibility our own modeset infrastructure
affords us and prefill default crtc timings. This allows us to rip out
->timings_set. Note that we overwrite things again when retrying the
pipe config computation due to bandwidth constraints to avoid bogus
crtc timings if the encoder only does relative adjustments (which is
how the pfit code works). Only a theoretical concern though since
platforms where we retry (pch-split platforms) do not need
adjustements (since only the old gmch pfit needs that). But let's
better be safe than sorry.

Since we now initialize the crtc timings before calling the
encoder->compute_config functions the crtc initialization in the gmch
pfit code is now redudant and so can be removed.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Add a paragraph to the commit message to explain why we can
ditch the crtc timings initialization call from the gmch pfit code, to
answer a question from Rodrigo's review.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The encoder->mode_set callback from the crtc helpers is now completely
unused in our driver. Good riddance!
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Everyone is now using our own ->compute_config callback, which means
we can now also make that callback mandatory.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need the correct clock to accurately assess whether we need to
enable the double wide pipe mode or not.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: Stuart Abercrombie <sabercrombie@google.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently, the register access code is split between i915_drv.c and
intel_pm.c. It only bares a superficial resemblance to the reset of the
powermanagement code, so move it all into its own file. This is to ease
further patches to enforce serialised register access.

v2: Scan for random abuse of I915_WRITE_NOTRACE
v3: Take the opportunity to rename the GT functions as uncore. Uncore is
the term used by the hardware design (and bspec) for all functions
outside of the GPU (and CPU) cores in what is also known as the System
Agent.
v4: Rebase onto SNB rc6 fixes
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Wrestle patch into applying and inline
intel_uncore_early_sanitize (plus move the old comment to the new
function). Also keep the _santize postfix for intel_uncore_sanitize.]
[danvet: Squash in fixup spotted by Chris on irc: We need to call
intel_pm_init before intel_uncore_sanitize since the later will call
cancel_work on the delayed rps setup work the former initializes.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For now there are no callers, but these functions are going to be
needed for the code that allows Package C8+. Other future features may
also require this code.

Also merge the commit which introduced assert_can_disable_lcpll and
had the following commit message:

Most of the hardware needs to be disabled before LCPLL is disabled, so
let's add a function to assert some of items listed in the "Display
Sequences for LCPLL disabling" documentation.

The idea is that hsw_disable_lcpll should not disable the hardware,
the callers need to take care of calling hsw_disable_lcpll only once
everything is already disabled.

v2: - Rebase.
    - Fix D_COMP wait timeout.
v3: - Use wait_for_atomic_use (Ben)
    - Remove/add a useless/needed POSTING_READ (Ben)
    - Early return in case LCPLL is already restored (Ben)
    - Add ndelay(100) (Ben)
v4: - Merge the commit that added assert_can_disable_lcpll (Ben)
    - Add interrupt assertions (Ben)
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Fix compile fail since there's no HAS_LP_PCH yet.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We currently don't support HDMI clock bending nor use SSC for DP or
HDMI on Haswell, so the only case where we need CLKOUT_DP is for VGA.

v2: - Replace the IS_ULT check for LPT-LP
    - Simplify GEN0/DBUFF0 check due to change on the previous patch
    - Also check for SBI_SSCCTL_DISABLE (Ben).
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now it implements 3 different sequences from BSpec and also has
support for ULT.

v2: - Change IS_ULT checks for LPT-LP checks
    - Add check for LPT-LP + with_fdi (Ben)
    - Merge DBUFF0/GEN0 bit definitions since they're the same
      register (Ben)
    - DBUFF0 (1<<0) is Disable, not Enable
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=47941
BugLink: https://bugs.launchpad.net/bugs/1163720
BugLink: https://bugs.launchpad.net/bugs/1162026

Some machines suffer from non-functional backlight controls if
BLM_PCH_PWM_ENABLE is set, so provide a quirk to avoid doing so.
Apply this quirk to Dell XPS 13 models.
Tested-by: NEric Griffith <EGriffith92@gmail.com>
Tested-by: NKent Baxley <kent.baxley@canonical.com>
Cc: <stable@vger.kernel.org> # v3.8+
Signed-off-by: NKamal Mostafa <kamal@canonical.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The next step is to modify lpt_enable_clkout_dp to enable support for
"Sequence to enable CLKOUT_DP" and "Sequence to enable CLKOUT_DP
without spread".
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Because lpt_init_pch_refclk implements the "Sequence to enable
CLKOUT_DP for FDI usage and configure PCH FDI I/O", which is very
similar to "Sequence to enable CLKOUT_DP" and "Sequence to enable
CLKOUT_DP without spread". With the extracted functions we can more
easily implement the two missing sequences.

v2: Rebase (WaMPhyProgramming:hsw comment).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The machines that fall in the "is_sdv" case are some very early
pre-production steppings. This patch may break VGA output after
suspend/resume on these machines.

Even the documentation for the is_sdv cases was removed from BSpec.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

PSR must be enabled after transcoder and port are running.
And it is only available for HSW.

v2: move enable/disable to intel_ddi
v3: The spec suggests PSR should be disabled even before backlight (by pzanoni)
v4: also disabling and enabling whenever panel is disabled/enabled.
v5: make it last patch to avoid breaking whenever bisecting. So calling for
    update and force exit came to this patch along with enable/disable calls.
v6: Remove unused and unecessary psr_enable/disable calls, as notice by Paulo.

CC: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Drop the psr exit code in the busy ioctl since I didn't merge
that part of the infrastructure yet - it needs more thought.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In commit e3de42b6
Author: Imre Deak <imre.deak@intel.com>
Date:   Fri May 3 19:44:07 2013 +0200

    drm/i915: force full modeset if the connector is in DPMS OFF mode

a new function was added that walked over the set of connectors to see
if any of the currently associated CRTC was switched off. This function
walked an array of connectors, rather than the array of pointers to
connectors contained in the drm_mode_set - i.e. it was dereferencing far
past the end of the first connector. This only becomes an issue if we
attempt to use a clone mode (i.e. more than one connector per CRTC) such
that set->num_connectors > 1.
Reported-by: NTimo Aaltonen <tjaalton@ubuntu.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65927Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Egbert Eich <eich@suse.de>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There seems to be no limit to the amount of gunk the firmware can
leave behind. Some platforms leave pch dplls on which are not in
active use at all. The example in the bug report is a Apple Macbook
Pro.

Note that this escape scrunity of the hw state checker until we've
tried to use this enabled, but unused pll since we did only check for
the inverse case of a in-used, but disabled pll.

v2: Add a WARN in the pll state checker which would have caught this
case.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66952Reported-and-tested-by: Nshui yangwei <yangweix.shui@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Toghether with the hw state readout this should catch cases where we
don't properly updated the pll state (either in sw or hw). At least
for the shared dpll code the equivalent tricke helped a lot in
catching bugs.

Also rename the function prefix, it's not a generic piece of
infrastructure.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Bspec for the "DPLL HDMI multiplier" field says:

"Restriction : The DPLL must be enabled and stable before setting these bits.
These bits must be programmed after DPLL_SEL is programmed."

There is apparently no restriction on programming the DPLL_SEL
register wrt the DPLL. So let's just move that up before we enable the
pch dpll.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No need to call the ->pre_pll_enable hook twice if we don't enable the
dpll too early. This should make Jani a bit less grumpy.

v2: Rebase on top of the newly-colored BUG_ONs.

v3: Reinstate the lost write of the DPLL_MD register, spotted by Imre.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Move error state generation and stringification to it's
own compilation unit. Sysfs also uses this so it can't be
under CONFIG_DEBUG_FS

This fixes a regression introduced in

commit ef86ddce
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Thu Jun 6 17:38:54 2013 +0300

    drm/i915: add error_state sysfs entry

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66814Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Came accross two open coding of for_each_pipe(), might as well use the
macro.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>