irq handlers always run with interrupts locally disabled, so
plain spinlocks is all we need. I've also reviewed again that they
all follow the _irq_handler postfix convention.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

All the interrupt setup/teardown hooks are always run from plain
process context. So again just the _irq variant is good enough.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Work functions are in process context, so plain _irq spinlock variants
is all we need.

The hpd reenable work didn't follow the _work/_work_func postfix
naming scheme, so adjust that while at it.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We want to enable/disable display IRQs only if global i915 IRQs are
enabled. To check the latter it's not enough to consult the DRM
dev->irq_enabled flag, since runtime PM can disable/enable IRQs
and it won't adjust this flag only the i915 specific
dev_priv->pm._irqs_disabled flag. Fix this by using the proper
intel_irqs_enabled() helper instead.

Fortunately this didn't cause an actual problem since even if we enabled
display IRQs too early (before enabling global i915 IRQs) the
VLV_MASTER_IER would still be clear masking all IRQs.

This issue was caught by

commit 920dd15a2b2fc60d054646a8a1ffd6aeb6090e05
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Aug 27 10:43:37 2014 +0200

    drm/i915: WARN if interrupts aren't on in en/disable_pipestat
Signed-off-by: NImre Deak <imre.deak@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that vlv has runtime pm we kinda should check for that like on the
pch split platforms. Looks like this was simply lost in the vlv rpm
enabling.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

I've read INVBL as "invalid backlight" and got mightly confused.
The #defines are already fairly long and we can afford to extend
them a bit more without resulting in ugly code all over.

I'm not sure how useful the complicated bitmask return value of these
functions really are since no one checks them. But for now let's keep
things as is.

Cc: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NMario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Long ago, back in the racy haydays of 915gm interrupt handling, page
flips would occasionally go astray and leave the hardware stuck, and the
display not updating. This annoyed people who relied on their systems
being able to display continuously updating information 24/7, and so
some code to detect when the driver missed the page flip completion
signal was added. Until recently, it was presumed that the interrupt
handling was now flawless, but once again Simon Farnsworth has found a
system whose display will stall. Reinstate the pageflip stall detection,
which works by checking to see if the hardware has been updated to the
new framebuffer address following each vblank. If the hardware is
scanning out from the new framebuffer, but we still think the flip is
pending, then we kick our driver into submision.

This is a continuation of the effort started with
commit 4e5359cd
Author: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Date:   Wed Sep 1 17:47:52 2010 +0100

    drm/i915: Avoid pageflipping freeze when we miss the flip prepare interrupt

This now includes a belt-and-braces approach to make sure the driver
(or the hardware) doesn't miss an interrupt and cause us to stop
updating the display should the unthinkable happen and the pageflip fail - i.e.
that the user is able to continue submitting flips.

v2: Cleanup, refactor, and rename
v3: Only start counting vblanks after the flip command has been seen by
    the hardware.
v4: Record the seqno after we touch the ring, or else there may be no
    seqno allocated yet.
v5: Rebase on mmio-flip.
v6: Rebase, rebase.
Reported-by: NSimon Farnsworth <simon@farnz.org.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75502Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> [v4]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A few open coded HAS_GMCH_DISPLAY() remain in the underrun reporting
code. Convert them over.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

WaGsvRC0ResidenncyMethod is for vlv, it doesn't deal with chv
appropriately (eg. doesn't limit rps values to even numbers).

Fix a typo in the w/a name while at it.

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

BDW supports GT C0 residency reporting in constant time unit. Driver
calculates GT utilization based on C0 residency and adjusts RP
frequency up/down accordingly. For offscreen workload specificly,
set frequency to RP0.

Offscreen task is not restricted by frame rate, it can be
executed as soon as possible. Transcoding and serilized workload
between CPU and GPU both need high GT performance, RP0 is a good
option in this case. RC6 will kick in to compensate power
consumption when GT is not active.

v2: Rebase on recent drm-intel-nightly
v3: Add flip timerout monitor, when no flip is deteced within
100ms, set frequency to RP0.
Signed-off-by: NDaisy Sun <daisy.sun@intel.com>
[torourke: rebased on latest and resolved conflict]
Signed-off-by: NTom O'Rourke <Tom.O'Rourke@intel.com>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Programing GT IER interrupts was fumbled while enabling Interrupts for
gen8

We forgot to program PM IER interrupt in gen8_gt_irq_postinstall based
on the new  re-worked interrupt routines.

v2: Kill the loop and init GT interrupts individually (Ville)
Signed-off-by: NDeepak S <deepak.s@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Adjust commit message as per discussion with Deepak.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Chris has decided that enough is enough. It's time to fixup dev Vs
dev_priv. This is a modest contribution to the crusade.

v2: Still use INTEL_INFO(), for the (mythical!) case we want to hardcode
    the info struct with defines (Chris)
    Rename the macro argument from 'dev' to 'dev_priv' (Jani)

v3: Use names unlikely to be used as macro arguments (Chris)
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm, the HPD IRQ reenable timer can get rearmed right after it's
canceled. Also to access the HPD IRQ mask registers we need to wake up
the HW.

Solve both issues by converting the reenable timer to a delayed work and
grabbing a runtime PM reference in the work. By this we can also forgo
canceling the timer during runtime suspend, since the only important
thing there is that the HW is awake when we write the registers and
that's ensured by the RPM ref. So do the cancelation only during driver
unload time; this is also a requirement for an upcoming patch where we
want to cancel all HPD related works only during system suspend and
driver unload time, but not during runtime suspend.

Note that there is still a race between the HPD IRQ reenable work and
drm_irq_uninstall() during driver unload, where the work can reenable
the HPD IRQs disabled by drm_irq_uninstall(). This isn't a problem since
the HPD IRQs will still be effectively masked by the first level
interrupt mask.

v2-3:
- unchanged
v4:
- use proper API for changing the expiration time for an already pending
  delayed work (Jani)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v2)
Cc: stable@vger.kernel.org (3.16+)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Handle all context status events in the context status buffer on every
context switch interrupt. We only remove work from the execlist queue
after a context status buffer reports that it has completed and we only
attempt to schedule new contexts on interrupt when a previously submitted
context completes (unless no contexts are queued, which means the GPU is
free).

We canot call intel_runtime_pm_get() in an interrupt (or with a spinlock
grabbed, FWIW), because it might sleep, which is not a nice thing to do.
Instead, do the runtime_pm get/put together with the create/destroy request,
and handle the forcewake get/put directly.
Signed-off-by: NThomas Daniel <thomas.daniel@intel.com>

v2: Unreferencing the context when we are freeing the request might free
the backing bo, which requires the struct_mutex to be grabbed, so defer
unreferencing and freeing to a bottom half.

v3:
- Ack the interrupt inmediately, before trying to handle it (fix for
missing interrupts by Bob Beckett <robert.beckett@intel.com>).
- Update the Context Status Buffer Read Pointer, just in case (spotted
by Damien Lespiau).

v4: New namespace and multiple rebase changes.

v5: Squash with "drm/i915/bdw: Do not call intel_runtime_pm_get() in an
interrupt", as suggested by Daniel.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch ...]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to attend context switch interrupts from all rings. Also, fixed writing
IMR/IER and added HWSTAM at ring init time.

Notice that, if added to irq_enable_mask, the context switch interrupts would
be incorrectly masked out when the user interrupts are due to no users waiting
on a sequence number. Therefore, this commit adds a bitmask of interrupts to
be kept unmasked at all times.

v2: Disable HWSTAM, as suggested by Damien (nobody listens to these interrupts,
anyway).

v3: Add new get/put_irq functions.

Signed-off-by: Thomas Daniel <thomas.daniel@intel.com> (v1)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v2 & v3)
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Drop the GEN8_ prefix from the context switch interrupt
define and move it to its brethren.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Don't print raw numbers, use port_name() and tell the user whether it's
long or short without having to figure out what the other magic number
means.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

adj was defined as u8. The issue is last_adj can be negative and adj is
initialized with:

  adj = dev_priv->rps.last_adj;

and we were also happily doing things like:

  if (adj < 0)

(thank static analysers!)

v2: Make new_delay an int in case we overflow the u8 in the intermediate
    computations. new_delay will get clamped at the end anyway. (Ville)

Cc: Deepak S <deepak.s@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Following the established idom, let's provide a macro to iterate through
the encoders.

spatch helps, once more, for the substitution:

  @@
  iterator name list_for_each_entry;
  iterator name for_each_intel_encoder;
  struct intel_encoder * encoder;
  struct drm_device * dev;
  @@
  -list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head) {
  +for_each_intel_encoder(dev, encoder) {
    ...
  }

I also modified a few call sites by hand where a pointer to mode_config
was directly used (to avoid overflowing 80 chars).
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Wrap paramters correctly in the macro and remove spurious
space checkpatch noticed.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since we started using intel_runtime_pm_disable_interrupts() at normal
(non-runtime) suspend/resume, we had to remove a WARN from
ironlake_disable_display_irq to avoid a case where we were doing the
correct thing and the WARN was not really needed. The problem is that
the WARN was useful in other cases, and its removal can hide some bugs
that we would catch automatically.

To be able to add back the WARN, we have to call intel_crtc_control()
before interrupts are disabled, which is what this patch currently
does.

Also notice that Ville's patch from the Watermarks series "drm/i915:
Leave interrupts enabled while disabling crtcs during suspend" also
did a change that's equivalent to the one we're doing on this patch,
with the exception that its original patch, when applied to the
current tree, procduces a WARN.

Related commits:

commit daa390e5ee45cc051d6bf37b296901f2f92b002d
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
    drm/i915: don't warn if IRQs are disabled when shutting down display IRQs

commit e11aa362
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
    drm/i915: use runtime irq suspend/resume in freeze/thaw

Note that the function part of this patch has already been done in

commit 0e32b39c
Author: Dave Airlie <airlied@redhat.com>
Date:   Fri May 2 14:02:48 2014 +1000

    drm/i915: add DP 1.2 MST support (v0.7)

with the fixup

commit 09b64267
Author: Dave Airlie <airlied@redhat.com>
Date:   Wed Jul 23 14:25:24 2014 +1000

    drm/i915: don't suspend gt until after we disable irqs and display (v2)

so all that's left from Paulo's patch is reinstating the WARNING.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Explain conflict resolution with Dave's DP MST patches with a
note in the commit message.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Share the waitqueue that drm_irq uses when performing the vblank evade
trick for atomic pipe updates.

v2: Keep intel_pipe_handle_vblank() (Chris)
Suggested-by: NDaniel Vetter <daniel@ffwll.ch>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the actual head has progressed forward inside a batch (request),
don't accumulate hangcheck score.

As the hangcheck score in increased only by acthd jumping backwards,
the result is that we only declare an active batch as stuck if it is
trapped inside a loop. Or that the looping will dominate the batch
progression so that it overcomes the bonus that forward progress gives.

v2: Improved commit message (Chris Wilson)
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
[danvet: s/active_loop/active (loop)/ as requested by Chris.]
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that the vblank races are plugged, we can opt out of using
the vblank disable timer and just let vblank interrupts get
disabled immediately when the last reference is dropped.

Gen2 is the exception since it has no hardware frame counter.
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Before we've installed the handler, we can set this and avoid confusing
init code that then thinks IRQs are enabled and spews complaints
everywhere.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we use the runtime IRQ enable/disable functions in our suspend
path, we can simply check the pm._irqs_disabled flag everywhere.  So
rename it to catch the users, and add an inline for it to make the
checks clear everywhere.
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>

This was always the case on our suspend path, but it was recently
exposed by the change to use our runtime IRQ disable routine rather than
the full DRM IRQ disable.  Keep the warning on the enable side, as that
really would indicate a bug.
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>

Move it from hsw_power_well_post_enable() (intel_pm.c) to i915_irq.c
so we can reuse the nice IRQ macros we have there. The main difference
is that now we're going to check if the IIR register is non-zero when
we try to re-enable the interrupts.
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>

If we enable unclaimed register reporting on Gen 8, we will discover
that the IRQ registers for pipes B and C are also on the power well,
so writes to them when the power well is disabled result in unclaimed
register errors.

Also, hsw_power_well_post_enable() already takes care of re-enabling
them once the power well is enabled.

Testcase: igt/pm_rpm/rte
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>

Traditionally we use genX_ for GT/render stuff and the codenames for
display stuff. But the gt and pm interrupt handling functions on
gen5/6+ stuck out as exceptions, so convert them.

Looking at the diff this nicely realigns our ducks since almost all
the callers are already platform-specific functions following the
genX_ pattern.

Spotted while reviewing some internal rps patches.

No function change in this patch.
Acked-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No need to list all the platforms explicitly.

The prefix is a bit inconsistent since we usually pick gen8_ for GT
related functions. But this anti-pattern is already established with snb,
so material for a different patch.

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

This adds DP 1.2 MST support on Haswell systems.

Notes:
a) this reworks irq handling for DP MST ports, so that we can
avoid the mode config locking in the current hpd handlers, as
we need to process up/down msgs at a better time.

Changes since v0.1:
use PORT_PCH_HOTPLUG to detect short vs long pulses
add a workqueue to deal with digital events as they can get blocked on the
main workqueue beyong mode_config mutex
fix a bunch of modeset checker warnings
acks irqs in the driver
cleanup the MST encoders

Changes since v0.2:
check irq status again in work handler
move around bring up and tear down to fix DPMS on/off
use path properties.

Changes since v0.3:
updates for mst apis
more state checker fixes
irq handling improvements
fbcon handling support
improved reference counting of link - fixes redocking.

Changes since v0.4:
handle gpu reset hpd reinit without oopsing
check link status on HPD irqs
fix suspend/resume

Changes since v0.5:
use proper functions to get max link/lane counts
fix another checker backtrace - due to connectors disappearing.
set output type in more places fro, unknown->displayport
don't talk to devices if no HPD asserted
check mst on short irqs only
check link status properly
rebase onto prepping irq changes.
drop unsued force_act

Changes since v0.6:
cleanup unused struct entry.

[airlied: fix some sparse warnings].
Reviewed-by: NTodd Previte <tprevite@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

commit 4be17381
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jun 6 10:22:29 2014 +0100

    drm/i915: Reorder semaphore deadlock check

did the majority of the work, but it missed one crucial detail:

The check for the unkickable deadlock on this ring must come after the
check whether the ring that we are waiting on has already passed its
target seqno.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80709Tested-by: NStefan Huber <shuber@sthu.org>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

DP MST will need connectors that aren't connected to specific
encoders, add some checks in advance to avoid oopses.
Reviewed-by: NTodd Previte <tprevite@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Enabled PM interrupt programming for CHV. Re-using gen8 code and extending same for CHV.
Signed-off-by: NDeepak S <deepak.s@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Place the RPS counters inside the RPS struct.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With RC6 enabled, BYT has an HW issue in determining the right
Gfx busyness.
WA for Turbo + RC6: Use SW based Gfx busy-ness detection to decide
on increasing/decreasing the freq. This logic will monitor C0
counters of render/media power-wells over EI period and takes
necessary action based on these values

v2: Refactor duplicate code. (Ville)

v3: Reformat the comments. (Ville)

v4: Enable required counters and remove unwanted code (Ville)

v5: Added frequency change acceleration support and remove kernel-doc
style comments. (Ville)

v6: Updated comment section and Fix w/a comment. (Ville)
Signed-off-by: NDeepak S <deepak.s@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some drivers need to be able to have a perfect race-free fbcon setup.
Current drivers only enable hotplug processing after the call to
drm_fb_helper_initial_config which leaves a tiny but important race.

This race is especially noticable on embedded platforms where the
driver itself enables the voltage for the hdmi output, since only then
will monitors (after a bit of delay, as usual) respond by asserting
the hpd pin.

Most of the infrastructure is already there with the split-out
drm_fb_helper_init. And drm_fb_helper_initial_config already has all
the required locking to handle concurrent hpd events since

commit 53f1904b
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Mar 20 14:26:35 2014 +0100

    drm/fb-helper: improve drm_fb_helper_initial_config locking

The only missing bit is making drm_fb_helper_hotplug_event save
against concurrent calls of drm_fb_helper_initial_config. The only
unprotected bit is the check for fb_helper->fb.

With that drivers can first initialize the fb helper, then enabel
hotplug processing and then set up the initial config all in a
completely race-free manner. Update kerneldoc and convert i915 as a
proof of concept.

Feature requested by Thierry since his tegra driver atm reliably boots
slowly enough to misses the hotplug event for an external hdmi screen,
but also reliably boots to quickly for the hpd pin to be asserted when
the fb helper calls into the hdmi ->detect function.

Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Ipehr just carries Dword 0 and on Gen 8, offsets are located
on Dword 2 and 3 of MI_SEMAPHORE_WAIT.

This implementation was based on Ben's work and on Ville's suggestion for Ben

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Fixup format string.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The digital ports from Ironlake and up have the ability to distinguish
between long and short HPD pulses. Displayport 1.1 only uses the short
form to request link retraining usually, so we haven't really needed
support for it until now.

However with DP 1.2 MST we need to handle the short irqs on their
own outside the modesetting locking the long hpd's involve. This
patch adds the framework to distinguish between short/long to the
current code base, to lay the basis for future DP 1.2 MST work.

This should mean we get better bisectability in case of regression
due to the new irq handling.

v2: add GM45 support (untested, due to lack of hw)
Signed-off-by: NDave Airlie <airlied@redhat.com>
Reviewed-by: NTodd Previte <tprevite@gmail.com>
[danvet: Fix conflicts in i915_irq.c with Oscar Mateo's irq handling
race fixes and a trivial one in intel_drv.h with the psr code.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise, we might receive a new interrupt before we have time to
ack the first one, eventually missing it.

Without an atomic XCHG operation with mmio space, this patch merely
reduces the window in which we can miss an interrupt (especially when
you consider how heavyweight the I915_READ/I915_WRITE operations are).

Notice that, before clearing a port-sourced interrupt in the IIR, the
corresponding interrupt source status in the PORT_HOTPLUG_STAT must be
cleared.

Spotted by Bob Beckett <robert.beckett@intel.com>.

v2:
- Add warning to commit message and comments to the code as per Chris
  Wilson's request.
- Imre Deak pointed out that the pipe underrun flag might not be signaled
  in IIR, so do not make valleyview_pipestat_irq_handler depend on it.

v3: Improve the source code comment.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise, we might receive a new interrupt before we have time to
ack the first one, eventually missing it.

The right order should be:

1 - Disable Master Interrupt Control.
2 - Find the category of interrupt that is pending.
3 - Find the source(s) of the interrupt and clear the Interrupt Identity bits (IIR)
4 - Process the interrupt(s) that had bits set in the IIRs.
5 - Re-enable Master Interrupt Control.

Without an atomic XCHG operation with mmio space, the above merely reduces the window
in which we can miss an interrupt (especially when you consider how heavyweight the
I915_READ/I915_WRITE operations are).

Spotted by Bob Beckett <robert.beckett@intel.com>.

v2: Add warning to commit message and comments to the code as per Chris Wilson's request.

v3: Improve the source code comment.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>