We currently disable the ERR_INT interrupts while running the IRQ
handler because we fear that if we do an unclaimed register access
from inside the IRQ handler we'll keep triggering the IRQ handler
forever.

The problem is that since we always disable the ERR_INT interrupts at
the IRQ handler, when we get a FIFO underrun we'll always print both
messages:
  - "uncleared fifo underrun on pipe A"
  - "Pipe A FIFO underrun"

Because the "was_enabled" variable from
ivybridge_set_fifo_underrun_reporting will always be false (since we
disable ERR int at the IRQ handler!).

Instead of actually fixing ivybridge_set_fifo_underrun_reporting,
let's just remove the "disable ERR_INT during the IRQ handler" code.
As far as we know we shouldn't really be triggering ERR_INT interrupts
from the IRQ handler, so if we ever get stuck in the endless loop of
interrupts we can git-bisect and revert (and we can even bisect and
revert this patch in case I'm just wrong). As a bonus, our IRQ handler
is now simpler and a few nanoseconds faster.
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>

We'd only ever used this define to denote whether or not we have the
dynamic parity feature (DPF) and never to determine whether or not L3
exists. Baytrail is a good example of where L3 exists, and not DPF.

This patch provides clarify in the code for future use cases which might
want to actually query whether or not L3 exists.

v2: Add /* DPF == dynamic parity feature */
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Certain HSW SKUs have a second bank of L3. This L3 remapping has a
separate register set, and interrupt from the first "slice". A slice is
simply a term to define some subset of the GPU's l3 cache. This patch
implements both the interrupt handler, and ability to communicate with
userspace about this second slice.

v2:  Remove redundant check about non-existent slice.
Change warning about interrupts of unknown slices to WARN_ON_ONCE
Handle the case where we get 2 slice interrupts concurrently, and switch
the tracking of interrupts to be non-destructive (all Ville)
Don't enable/mask the second slice parity interrupt for ivb/vlv (even
though all docs I can find claim it's rsvd) (Ville + Bryan)
Keep BYT excluded from L3 parity

v3: Fix the slice = ffs to be decremented by one (found by Ville). When
I initially did my testing on the series, I was using 1-based slice
counting, so this code was correct. Not sure why my simpler tests that
I've been running since then didn't pick it up sooner.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reduces dmesg noise when there's a glitch on the hpd line, or there
are more than one connectors on the same hpd line and only one of them
changes.

While at it, switch to use the friendly status names instead of numbers.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Score and action reveals what all the rings were doing
and why hang was declared. Add idle state so that
we can distinguish between waiting and idle ring.

v2: - add idle as a hangcheck action
    - consensed hangcheck status to single line (Chris)
    - mark active explicitly when we are making progress (Chris)
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Historically we've run our own driver hotplug handling in our own
work-queue, which then launched the drm core hotplug handling in the
system workqueue. This is important since we flush our own driver
workqueue in the pageflip code while hodling modeset locks, and only
the drm hotplug code grabbed these locks. But with

commit 69787f7d
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Oct 23 18:23:34 2012 +0000

    drm: run the hpd irq event code directly

this was changed and now we could deadlock in our flip handler if
there's a hotplug work blocking the progress of the crucial unpin
works. So this broke the careful deadlock avoidance implemented in

commit b4a98e57
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 1 09:26:26 2012 +0000

    drm/i915: Flush outstanding unpin tasks before pageflipping

Since the rule thus far has been that work items on our own workqueue
may never grab modeset locks simply restore that rule again.

v2: Add a comment to the declaration of dev_priv->wq to warn readers
about the tricky implications of using it. Suggested by Chris Wilson.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Stuart Abercrombie <sabercrombie@chromium.org>
Reported-by: NStuart Abercrombie <sabercrombie@chromium.org>
References: http://permalink.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/26239
Cc: stable@vger.kernel.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Squash in a comment at the place where we schedule the work.
Requested after-the-fact by Chris on irc since the hpd work isn't the
only place we botch this.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We already have a big splashing *ERROR* for all the relevant cases of
hangs, so this one here is redudant. And it results in an unclean
dmesg when running with simulated hangs. Regression has been
introduced in

commit 05407ff8
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Thu May 30 09:04:29 2013 +0300

    drm/i915: detect hang using per ring hangcheck_score

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68641Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

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>

Because hsw_pm_irq_handler does exactly what gen6_rps_irq_handler does
and also processes the 2 additional VEBOX bits. So merge those
functions and wrap the VEBOX bits on a HAS_VEBOX check. This
check isn't really necessary since the bits are reserved on
SNB/IVB/VLV, but it's a good documentation on who uses them.

v2: - Change IS_HASWELL check to HAS_VEBOX
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>

It seems we've been doing this ever since we started processing the
RPS events on a work queue, on commit "drm/i915: move gen6 rps
handling to workqueue", 4912d041.

The problem is: when we add work to the queue, instead of just masking
the bits we queued and leaving all the others on their current state,
we mask the bits we queued and unmask all the others. This basically
means we'll be unmasking a bunch of interrupts we're not going to
process. And if you look at gen6_pm_rps_work, we unmask back only
GEN6_PM_RPS_EVENTS, which means the bits we unmasked when adding work
to the queue will remain unmasked after we process the queue.

Notice that even though we unmask those unrelated interrupts, we never
enable them on IER, so they don't fire our interrupt handler, they
just stay there on IIR waiting to be cleared when something else
triggers the interrupt handler.

So this patch does what seems to make more sense: mask only the bits
we add to the queue, without unmasking anything else, and so we'll
unmask them after we process the queue.

As a side effect we also have to remove that WARN, because it is not
only making sure we don't mask useful interrupts, it is also making
sure we do unmask useless interrupts! That piece of code should not be
responsible for knowing which bits should be unmasked, so just don't
assert anything, and trust that snb_disable_pm_irq should be doing the
right thing.

With i915.enable_pc8=1 I was getting ocasional "GEN6_PMIIR is not 0"
error messages due to the fact that we unmask those unrelated
interrupts but don't enable them.

Note: if bugs start bisecting to this patch, then it probably means
someone was relying on the fact that we unmask everything by accident,
then we should fix gen5_gt_irq_postinstall or whoever needs the
accidentally unmasked interrupts. Or maybe I was just wrong and we
need to revert this patch :)

Note: This started to be a more real issue with the addition of the
VEBOX support since now we do enable more than just the minimal set of
RPS interrupts in the IER register. Which means after the first rps
interrupt has happened we will never mask the VEBOX user interrupts
again and so will blow through cpu time needlessly when running video
workloads.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Add note that this started to matter with VEBOX much more.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On SNB/IVB/VLV we only call gen6_rps_irq_handler if one of the IIR
bits set is part of GEN6_PM_RPS_EVENTS, but at gen6_rps_irq_handler we
add all the enabled IIR bits to the work queue, not only the ones that
are part of GEN6_PM_RPS_EVENTS. But then gen6_pm_rps_work only
processes GEN6_PM_RPS_EVENTS, so it's useless to add anything that's
not GEN6_PM_RPS_EVENTS to the work queue.

As a bonus, gen6_rps_irq_handler looks more similar to
hsw_pm_irq_handler, so we may be able to merge them in the future.

v2: - Add a WARN in case we queued something we're not going to
      process.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the error interrupts are already disabled, don't disable and
reenable them. This is going to be needed when we're in PC8+, where
all the interrupts are disabled so we won't risk re-enabling
DE_ERR_INT_IVB.

v2: Use dev_priv->irq_mask (Chris)
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>

Just like irq_mask and gt_irq_mask, use it to track the status of
GEN6_PMIMR so we don't need to read it again every time we call
snb_update_pm_irq.
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>

I did some brief tests and the "new_val = pmimr" condition usually
happens a few times after exiting games.

Note: This is also prep work to track the GEN6_PMIMR register state in
dev_priv->pm_imr. This happens in the next patch.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Add note to explain why we want this, as per the discussion
between Chris and Paulo.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just like we're doing with the other IMR changes.

One of the functional changes is that not every caller was doing the
POSTING_READ.
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>

Just like the functions that touch DEIMR and SDEIMR, but for GTIMR.
The new functions contain a POSTING_READ(GTIMR) which was not present
at the 2 callers inside i915_irq.c.

The implementation is based on ibx_display_interrupt_update.
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>

Although I could not reproduce this (different compiler version,
perhaps), reportedly we get:

drivers/gpu/drm/i915/i915_irq.c:1943:27: warning: ‘score’ may be used
uninitialized in this function [-Wuninitialized]

Drop the 'score' variable altogether as it's not really needed.
Reported-by: NKees Cook <keescook@chromium.org>
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 short lowercase names are bound to collide. The default warnings
don't even warn about shadowing.
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>

It's been there since i8xx_irq_handler() was added in
commit c2798b19
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Sun Apr 22 21:13:57 2012 +0100

    drm/i915: i8xx interrupt handler
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>

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

For HPD storm detection we now mask out individual interrupt source
bits. We have already seen a case where HPD interrupt enable bits
were assigned to the wrong pins. To track these conditions more
easily add some debugging messages.

v2: Spelling fixes 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>

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>

Requested by Chris Wilson on IRC.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Make the uevent strings part of the user API for people who wish to
write their own listeners.

v2: Make a space in the string concatenation. (Chad)
Use the "UEVENT" suffix intead of "EVENT" (Chad)
Make kernel-doc parseable Docbook comments (Daniel)

v3: Undid reset change introduced in last submission (Daniel)
Fixed up comments to address removal changes.

Thanks to Daniel Vetter for a majority of the parity error comments.

CC: Chad Versace <chad.versace@linux.intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It was very similar to ironlake_irq_postinstall, so IMHO merging both
functions results in a code that is easier to maintain.

With this change, all the irq handler vfuncs between ironlake and
ivybridge are now unified.

v2: Add "(" and ")" to make at least one vim user much happier (Chris)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The IVB funtions are exactly the same as the ILK ones, with the
exception of the bit register. So add IVB/HSW support to
ironlake_enable_vblank and ironlake_disable_vblank, then kill the
ivybridge functions.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And then rename it to ironlake_irq_handler. Also move
ilk_gt_irq_handler up to avoid forward declarations.

In the previous patches I did small modifications to both
ironlake_irq_handler an ivybridge_irq_handler so they became very
similar functions. Now it should be very easy to verify that all we
need to add ILK/SNB support is to call ilk_gt_irq_handler, call
ilk_display_irq_handler and avoid reading pm_iir on gen 5.

v2: - Rebase due to changes on the previous patches
    - Move pm_iir to a tighter scope (Chris)
    - Change some Gen checks for readability
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have this POSTING_READ inside ironlake_irq_handler. I suppose we
also want it on IVB because we want to stop the IRQ handler as soon as
possible at this point.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The ironlake_irq_handler and ivybridge_irq_handler functions do
basically the same thing, but they have different implementation
styles. With this patch we reorganize ironlake_irq_handler in a way
that makes it look very similar to ivybridge_irq_handler.

One of the advantages of this new function style is that we don't
write 0 to the IIR registers anymore.

v2: - Rebase due to changes on previous patches
    - Move pm_iir to a tighter scope (Chris)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The register doesn't exist on Gen 5.

v2: Simplify checks since pm_iir is always 0 on Gen 5 (Chris)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just like we did with ilk_display_irq_handler.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It's the code that deals with de_iir.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After Daniel's latest changes it's now equal to
ironlake_irq_preinstall.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

To run hangcheck in near future.
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>

Again extract a common helper. For the postinstall hook things are a
bit more complicated since we have more cases on ilk-hsw/vlv here.

But since vlv was clearly broken by failing to initialize
dev_priv->gt_irq_mask correctly the shared code is clearly justified.

Also kill the PMIER setting in the async rps enable work. I should
have been save, but also clearly looked rather fragile. PMIER setup is
now all down in the irq pre/postinstall hooks.

With this we now have the usual interrupt register sequence for GT/PM
irq registers:

- IER is setup once with all the interrupts we ever need in the
  postinstall hook and never touched again. Exceptions are SDEIER,
  which is touched in the preinstall hook (when the irq handler isn't
  enabled) and then only from the irq handler. And DEIER/VLV_IER with
  is used in the irq handler but also written to once in the
  postinstall hook. But since that write is essentially what enables
  the interrupt and we should always have MSI interrupts we should be
  save. In case we ever have non-MSI interrupts we'd be screwed.

- IIR is cleared in the postinstall hook before we enable/unmask the
  respective interrupt sources. Hence we can't steal an interrupt
  event an accidentally trigger the spurious interrupt logic in the
  core kernel. Note that after some discussion with Ben Widawsky we
  think that we actually should clear the IIR registers in the
  preinstall hook. But doing that is a much larger patch series.

- IMR regs are (usually) all masked off. Those are the only regs
  changed at runtime, which is all protected by dev_priv->irq_lock.

This unification also kills the cargo-culted read-modify-write PM
register setup for VECS. Interrupt setup is done without userspace
being able to interfere, so we better know what values we want to put
into those registers. RMW cycles otoh are really good at papering over
races, until stuff magically blows up and no one has a clue why.

v2: Touch the gen6+ PM interrupt registers only on gen6+.

v3: Improve the commit message to more clearly spell out why we want
to unify the code and what exactly changes.

Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Add a comment to explain why the l3 parity interrupt is
special.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since the addition of VECS we have a slightly different enable
sequence for PM interrupts on ivb/hsw vs snb and vlv. Usually that
will end up in hard to track down surprises.

Hence unifiy things and since we have copies of this code in 3 places
now, extract it into its own little helper.

Note that this changes the irq preinstall sequence a bit for snb and
vlv: We now also clear the PM registers in the preinstall hook, in
addition to the PM register clearing/setup already done when actually
enabling rps. So this doesn't fix a bug but simply unifies the code
across all platforms. After the postinstall hook is similarly unified
we can rip out the then redundant PM interrupt setup from the rps
code.

v3: Rebase on top of the retained double-GTIIR clearing. Also
resurrect the masking/disabling of the gen6+ PM interrupts as spotted
by Ben Widaswky.

v4: Move the DE interrupt reset code out of gen5_gt_irq_preinstall
back to ironlake_irq_preinstall where it really belongs. Spotted by
Paulo.

v3: Improve the commit message to more clearly spell out why we want
to unify the code and what exactly changes.

Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: s/GT/PM/ to fix up a comment which Ben spotted while
reviewing.]
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>

The code to handle it is broken - there's simply no code to clear CS
parser errors on gen5+. And behold, for all the other rings we also
don't enable it!

Leave the handling code itself in place just to be consistent with the
existing mess though. And in case someone feels like fixing it all up.

This has been errornously enabled in

commit 12638c57
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Tue May 28 19:22:31 2013 -0700

    drm/i915: Enable vebox interrupts

Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that the rps interrupt locking isn't clearly separated (at elast
conceptually) from all the other interrupt locking having a different
lock stopped making sense: It protects much more than just the rps
workqueue it started out with. But with the addition of VECS the
separation started to blurr and resulted in some more complex locking
for the ring interrupt refcount.

With this we can (again) unifiy the ringbuffer irq refcounts without
causing a massive confusion, but that's for the next patch.

v2: Explain better why the rps.lock once made sense and why no longer,
requested by Ben.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

And kill the comment about it. Queueing work is a barrier type event,
no amount of locking will help in ordering things (as long as we queue
the work after having updated all relevant data structures). Also, the
queue_work works itself as a sufficient memory barrier.

Again on the surface this is just a tiny micro-optimization to reduce
the hold-time of dev_priv->irq_lock. But the better reason is that it
reduces superficial locking and so makes it clearer what we actually
need for correctness.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>