Grab bag for all the special cases:
- i9xx_check_fifo_underruns is only called from crtc_enable hooks,
  i.e. process context.
- i915_enable_asle_pipestat is only called from interrupt postinstall
  hooks. So again process context.
- gen8_irq_power_well_post_enable is called from the runtime pm code,
  which again means process context.
- The open-coded hpd_irq_setup loop in _thaw is also running in process
  context.

So for all of them the plain _irq variant is sufficient.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This was lost in

commit e11aa362
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Wed Jun 18 09:52:55 2014 -0700

    drm/i915: use runtime irq suspend/resume in freeze/thaw

which makes the second part of this commen a bit nonsense. Both were
originally added in

commit 15239099
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Mar 5 09:50:58 2013 +0100

    drm/i915: enable irqs earlier when resuming

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Somehow I've overlooked this when simplifying the irq reinit
scheme on gen4.5+ in

commit 78ad455f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu May 22 22:18:21 2014 +0200

    drm/i915: Improve irq handling after gpu resets

Since display interrups in general survive a gpu reset on those
platforms there's also no need to reinit the hotplug settings.

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

One step closer to dropping all the drm_bus_* code:
Add a driver->set_busid() callback and make all drivers use the generic
helpers. Nouveau is the only driver that uses two different bus-types with
the same drm_driver. This is totally broken if both buses are available on
the same machine (unlikely, but lets be safe). Therefore, we create two
different drivers for each platform during module_init() and set the
set_busid() callback respectively.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

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

Instead of going through hoops, just put the driver author directly as
DRM_AUTHOR() argument. This will also make it consistent when we add
Intel to the list.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On BDW we're seeing a problem that after we runtime resume, the
outputs connected to DDI C are not detected: they don't appear in the
SDEISR register and GMBUS transactions don't work. They stop working
at the moment we call intel_opregion_notify_adapter() during runtime
suspend, but they don't go back to work when we call the same function
during runtime resume. They only work after we do a modeset and call
intel_opregion_notify_encoder(), but this point is already too late.

While debugging, I tried to pass PCI_D3hot which is the value that
matches the spec, and it seems to have solved the problem. I couldn't
find any explanation of why this solves the problem, but there's also
no documented explanation - besides our code and git log - of why
Haswell should use PCI_D1, so keep this for now in order to keep BDW
runtime PM working.

Also add a comment to point the fact that there's no spec documenting
all the weirdness involved here.

Cc: kristen.c.accardi@intel.com
Testcase: igt/pm_rpm/drm-resources-equal
Testcase: igt/pm_rpm/i2c
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch is to address Daniels concerns over different code during reset:

http://lists.freedesktop.org/archives/intel-gfx/2014-June/047758.html

"The reason for aiming as hard as possible to use the exact same code for
driver load, gpu reset and runtime pm/system resume is that we've simply
seen too many bugs due to slight variations and unintended omissions."

Tested using igt drv_hangman.

V2: Cleaner way of preventing check_wedge returning -EAGAIN
V3: Clean the last_context during reset, to ensure do_switch() does the MI_SET_CONTEXT. As per review.
Signed-off-by: NMcAulay, Alistair <alistair.mcaulay@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
[danvet: Rebase over ctx->ppgtt rework and extend the comment in
check_wedge a bit.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Before sharing common parts between the system and runtime s/r
handlers we WARNed if the runtime s/r handlers were called on GENs that
didn't support RPM. But this WARN is not correct if the same handler is
called from the system s/r path, since that can happen on any platform.
This also broke system s/r on old platforms.

The issue was introduced in

commit 016970be
Author: Sagar Kamble <sagar.a.kamble@intel.com>
Date:   Wed Aug 13 23:07:06 2014 +0530

v2:
- remove the WARN and depend on the HAS_RUNTIME_PM check in
  rutime_suspend/resume instead (Daniel)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82751Signed-off-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Up until recently, semaphores weren't enabled in BDW so we didn't care
about them. But then Rodrigo came and enabled them:

   commit 521e62e4
   Author: Rodrigo Vivi <rodrigo.vivi@intel.com>

      drm/i915: Enable semaphores on BDW

So now we have to explicitly disable them for Execlists until both
features play nicely.
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm we may leave eDP VDD enabled during system suspend after the CRTCs
are disabled through an HPD->DPCD read event. So disable VDD during
suspend at a point when no HPDs can occur.

Note that runtime suspend doesn't have the same problem, since there the
RPM ref held by VDD provides already the needed serialization.

v2:
- add note to commit message about the runtime suspend path (Ville)
- use edp_panel_vdd_off_sync(), so we can keep the WARN in
  edp_panel_vdd_off() (Ville)
v3:
- rebased on -fixes (for_each_intel_encoder()->list_for_each_entry())
  (Imre)
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+)
[Jani: fix sparse warning reported by Fengguang Wu]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Make sure these work handlers don't run after we system suspend or
unload the driver. Note that we don't cancel the handlers during runtime
suspend. That could lead to a lockup, since we take a runtime PM ref
from the handlers themselves. Fortunaltely canceling there is not needed
since the RPM ref itself provides for the needed serialization.

v2:
- fix the order of canceling dig_port_work wrt. hotplug_work (Ville)
- zero out {long,short}_hpd_port_mask and hpd_event_bits for speed
  (Ville)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org (3.16+)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

On VLV, post S0i3 during i915_drm_thaw following issue is observed during ring
initialization.

[ 335.604039] [drm:stop_ring] ERROR render ring :timed out trying to stop ring
[ 336.607340] [drm:stop_ring] ERROR render ring :timed out trying to stop ring
[ 336.607345] [drm:init_ring_common] ERROR failed to set render ring head to zero ctl 00000000 head 00000000 tail 00000000 start 00000000
[ 337.610645] [drm:stop_ring] ERROR bsd ring :timed out trying to stop ring
[ 338.613952] [drm:stop_ring] ERROR bsd ring :timed out trying to stop ring
[ 338.613956] [drm:init_ring_common] ERROR failed to set bsd ring head to zero ctl 00000000 head 00000000 tail 00000000 start 00000000
[ 339.617256] [drm:stop_ring] ERROR render ring :timed out trying to stop ring
[ 339.617258] -----------[ cut here ]-----------
[ 339.617267] WARNING: CPU: 0 PID: 6 at drivers/gpu/drm/i915/intel_ringbuffer.c:1666 intel_cleanup_ring+0xe6/0xf0()
[ 339.617396] --[ end trace 5ef5ed1a3c92e2a6 ]--
[ 339.617428] [drm:__i915_drm_thaw] ERROR failed to re-initialize GPU, declaring wedged!

This is happening since wake is not enabled and Gunit registers are not restored.
For this system suspend/resume paths need to follow save/restore and additional
platform specific setup in suspend_complete and resume_prepare.

suspend_complete is shared unconditionaly for VLV, HSW, BDW. resume_prepare for
HSW and BDW has pc8 disabling which is needed during thaw_early so sharing
uncondtionally. For VLV and SNB runtime resume specific sequence exists.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Goel, Akash <akash.goel@intel.com>
Signed-off-by: NSagar Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With this change, intel_runtime_suspend and intel_runtime_resume functions
become completely platform agnostic. Platform specific suspend/resume
changes are moved to intel_suspend_complete and intel_resume_prepare.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Goel, Akash <akash.goel@intel.com>
Signed-off-by: NSagar Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Rather than take and release the console_lock() around a non-existent
DRM_I915_FBDEV, move the lock acquisation into the callee where it will
be compiled out by the config option entirely. This includes moving the
deferred fb_set_suspend() dance and encapsulating it entirely within
intel_fbdev.c.

v2: Use an integral work item so that we can explicitly flush the work
upon suspend/unload.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Add the flush_work in fbdev_fini per the mailing list
discussion. And s/BUG_ON/WARN_ON/ because.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 521e62e4.

Although POST_SYNC brought a bit of stability to Semaphores on BDW
it didn't solved all issues and some hungs can still occour when
semaphores are enabled on BDW. Also some sloweness can be found on some
igt tests, althoguth it apparently doesn't affect real workloads.

Besides that, no real performance gain was found on our tests with different
and even multiple workloads.

Let's disable it again for now. At least until we are sure it is safe
to re-enable it.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When I moved the irq disable down to after display disable,
I didn't realise the gt suspend also required irqs off, so move it
down as well.

Fixes WARNs seen at suspend/resume time.

v2: moved the rps flush down as well.
Tested-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

By the time I wrote this patch, it allowed me to catch some problems.
But due to patch reordering - in order to prevent fake "regression"
reports - this patch may be merged after the fixes of the problems
identified by this patch.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On VLV, after i915_pm_suspend display power wells are staying
power ungated. So, after initiating mem sleep "echo mem > /sys/power/state"
Display is staing D0 State. There might be better way/place to power gate
these wells. Also, we need to make sure that if wells are power gated due to
DPMS OFF sequence, they need not be turned off by i915_pm_suspend again.

v2: Extracted helper for intel_crtc_disable and power gating CRTC power wells.
[Daniel]

Cc: Imre Deak <imre.deak@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Change-Id: I34c80da66aa24c423a5576c68aa1f3a8d0f43848
Signed-off-by: NBorun Fu <borun.fu@intel.com>
Signed-off-by: NSagar Kamble <sagar.a.kamble@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>

To achieve further power savings during system freeze (aka connected
standby, or s0ix) we have to send a PCI_D1 opregion notification. As
the information about the state we're entering (system freeze,
suspend to ram or suspend to disk) is only available through the ACPI
subsystem, make this support depend on the relevant kconfig option.
Things will still work if this option isn't set, albeit with less than
optimial power saving.

This also fixes a compile breakage when the option is not set introduced
in

commit e5747e3a
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Jun 12 08:35:47 2014 -0700

    drm/i915: send proper opregion notifications on suspend/resume
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
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>

Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It is possible that, by the time we run i915_drm_freeze(),
delayed_resume_work was already queued but did not run yet. If it
still didn't run after intel_runtime_pm_disable_interrupts(), by the
time it runs it will try to change the interrupt registers with the
interrupts already disabled, which will trigger a WARN. We can
reliably reproduce this with the pm_rpm system-suspend test case.

In order to avoid the problem, we have to flush the work before
disabling the interrupts. We could also cancel the work instead of
flushing it, but that would require us to put a runtime PM reference -
and any other resource we may need in the future - in case the work
was already queued, so I believe flushing the work is more
future-proof, although less efficient. But I can also change this part
if someone requests.

Another thing I tried was to move the intel_suspend_gt_powersave()
call to before intel_runtime_pm_disable_interrupts(), but since that
function needs to be called after the interrupts are already disabled,
due to dev_priv->rps.work, this strategy didn't work.

Testcase: igt/pm_rpm/system-suspend
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80517Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We should be taking the right power well refs these days, so this
shouldn't be necessary.  It also gets in the way of re-using these
routines for S0iX states, as those need all the power saving features
enabled.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We don't need to uninstall the full handler, simply disabling interrupts
ought to be enough.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm, the forcewake refcount will be incorrectly set to zero during
system suspend if there is any reference held via the
i915_forcewake_user debugfs entry.

Fix this by simply not zeroing the sw counters during suspend and
restoring the original state using them. Note that the only other
places where we zeroed the counters were driver load and unload time,
where it was redundant anyway.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78059Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This matches the runtime suspend paths and allows the system to enter
the lowest power mode at freeze time.

v2: move disable_pc8 call to thaw_early (Imre)
    move enable_pc8 to freeze_late (Imre/Jesse)
v3: drop spurious hunk from _freeze now that we have freeze_late (Jesse)
v4: move back to suspend_late (Imre was right)
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This indicates to the firmware that it can power down various other
components or bring them back up, depending on the target system state.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This allows the system to enter the lowest power mode during system freeze.

v2: delete force wake timer at suspend (Imre)
v3: add GT work suspend function (Imre)
v4: use uncore forcewake reset (Daniel)
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We want to make sure everything is disabled and at its lowest power when
freezing.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

These are just single registers so wasting space for the pipe offsets
seems a bit pointless. So just use the _PIPE3() macro instead.

Also rewrite the _PIPE3() macro to be more obvious, and protect the
arguments properly.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Frob conflict.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

BDW uses IVB cursor offsets.

Whithout this patch it is not possible to use multiple outputs with cursor
on BDW.
The cursor gets completely crazy because update position uses the wrong
cursor register for the second pipe.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79621Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If both KMS is disabled (by i915.modeset=0 or nomodeset parameters) and
UMS is disabled (by CONFIG_DRM_I915_UMS=n, the default), the user might
not be aware his setup is not supported. Inform the users (and, by
extension, the poor i915 developers having to read their dmesgs in bug
reports) why their graphics experience might be lacking.

A similar message was added on the UMS path in
commit e147accb
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Thu Oct 10 15:25:37 2013 +0300

    drm/i915: tell the user KMS is required for gen6+

but it won't be reached if CONFIG_DRM_I915_UMS=n since
commit b30324ad
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Nov 13 22:11:25 2013 +0100

    drm/i915: Deprecated UMS support

v2: Use DRM_DEBUG_DRIVER.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently we do a full re-init of all interrupts after a gpu hang.
Which is pretty bad since we don't restore the interrupts we've
enabled at runtime correctly. Even with that addressed it's rather
horribly race.

But on g4x and later we only reset the gt and not the entire gpu.
Which means we only need to reset the GT interrupt bits. Which has the
nice benefit that vblank waits, pipe CRC interrupts and everything
else display related just keeps on working.

The downside is that gt interrupt handling (i.e. ring->get/put_irq) is
still racy. But as long as the gpu hang reliably wakes all waters and
we have a short time where the refcount drops to 0 we'll recover. So
not that bad really.

v2: Ville noticed that GTIMR and PMIMR don't get cleared, only the
subordinate per-ring registers. So let's rip out all the interrupt dancing.
The FIXME comment is still required though since the ring irq handling
happens at the per-ring interrupt mask registers, too.

Testcase: igt/kms_flip/vblank-vs-hang
Testcase: igt/kms_pipe_crc_basic/hang-*
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After the split-out of crtc locks from the big mode_config.mutex
there's still two major areas it protects:
- Various connector probe states, like connector->status, EDID
  properties, probed mode lists and similar information.
- The links from connector->encoder and encoder->crtc and other
  modeset-relevant connector state (e.g. properties which control the
  panel fitter).

The later is used by modeset operations. But they don't really care
about the former since it's allowed to e.g. enable a disconnected VGA
output or with a mode not in the probed list.

Thus far this hasn't been a problem, but for the atomic modeset
conversion Rob Clark needs to convert all modeset relevant locks into
w/w locks. This is required because the order of acquisition is
determined by how userspace supplies the atomic modeset data. This has
run into troubles in the detect path since the i915 load detect code
needs _both_ protections offered by the mode_config.mutex: It updates
probe state and it needs to change the modeset configuration to enable
the temporary load detect pipe.

The big deal here is that for the probe/detect users of this lock a
plain mutex fits best, but for atomic modesets we really want a w/w
mutex. To fix this lets split out a new connection_mutex lock for the
modeset relevant parts.

For simplicity I've decided to only add one additional lock for all
connector/encoder links and modeset configuration states. We have
piles of different modeset objects in addition to those (like bridges
or panels), so adding per-object locks would be much more effort.

Also, we're guaranteed (at least for now) to do a full modeset if we
need to acquire this lock. Which means that fine-grained locking is
fairly irrelevant compared to the amount of time the full modeset will
take.

I've done a full audit, and there's just a few things that justify
special focus:
- Locking in drm_sysfs.c is almost completely absent. We should
  sprinkle mode_config.connection_mutex over this file a bit, but
  since it already lacks mode_config.mutex this patch wont make the
  situation any worse. This is material for a follow-up patch.

- omap has a omap_framebuffer_flush function which walks the
  connector->encoder->crtc links and is called from many contexts.
  Some look like they don't acquire mode_config.mutex, so this is
  already racy. Again fixing this is material for a separate patch.

- The radeon hot_plug function to retrain DP links looks at
  connector->dpms. Currently this happens without any locking, so is
  already racy. I think radeon_hotplug_work_func should gain
  mutex_lock/unlock calls for the mode_config.connection_mutex.

- Same applies to i915's intel_dp_hot_plug. But again, this is already
  racy.

- i915 load_detect code needs to acquire this lock. Which means the
  w/w dance due to Rob's work will be nicely contained to _just_ this
  function.

I've added fixme comments everywhere where it looks suspicious but in
the sysfs code. After a quick irc discussion with Dave Airlie it
sounds like the lack of locking in there is due to sysfs cleanup fun
at module unload.

v1: original (only compile tested)

v2: missing mutex_init(), etc (from Rob Clark)

v3: i915 needs more care in the conversion:
- Protect the edp pp logic with the connection_mutex.
- Use connection_mutex in the backlight code due to
  get_pipe_from_connector.
- Use drm_modeset_lock_all in suspend/resume paths.
- Update lock checks in the overlay code.

Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NRob Clark <robdclark@gmail.com>

Atm, we disable GT power saving during the end of the suspend sequence
in i915_save_state(). Doing the disabling at that point seems arbitrary.
One reason to disable it early though is to have a quiescent HW state
before we do anything else (for example save registers). So move the
disabling earlier, which also takes care canceling of the deferred RPS
enabling work done by intel_disable_gt_powersave().

Note that after the move we'll call intel_disable_gt_powersave() only
in case modeset is enabled, but that's anyway the only case where we
have it enabled in the first place.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently user space can access GEM buffers mapped to GTT through
existing mappings concurrently while the platform specific suspend
handlers are running. Since these handlers may change the HW state in a
way that would break such accesses, remove the mappings before calling
the handlers. Spotted by Ville.

Also Chris pointed out that the lists that i915_gem_release_all_mmaps()
walks through need dev->struct_mutex, so take this lock. There is a
potential deadlock against a concurrent RPM resume, resolve this by
aborting and rescheduling the suspend (Daniel).

v2:
- take struct_mutex around i915_gem_release_all_mmaps() (Chris, Daniel)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Daniel keeps on ramping up the warning level of the DRM and our display
core to make it complain whenever the locking rules are not followed.
This caught

commit 24576d23
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Tue Mar 26 09:25:45 2013 -0700

    drm/i915: enable VT switchless resume v3

introducing an unlocked access to the CRTC whilst disabling it for
suspend.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78114Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We really just want to go detect displays again and fire off a hotplug
event if things have changed, not go through full hotplug processing.
Requested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>