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>

CHV has three pipes so let's expose them all.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NAntti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Unsurprisingly the cursor C regiters are also at a weird offset on CHV.
Add more pipe offsets to handle them.

This also gets rid of most of the differences between the i9xx vs. ivb
cursor code. We can unify the remaining code as well, but I'll leave
that for another patch.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NAntti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add support for the third pipe in cherrview

v2: Don't use spaces for indentation (Jani)
    Wrap long lines
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NRafael Barbalho <rafael.barbalho@intel.com>
[vsyrjala: slightly massaged the patch]
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Patch done using the following semantic patch (thanks Daniel for the
help!)

  @@
  iterator name list_for_each_entry;
  iterator name for_each_crtc;
  struct drm_crtc * crtc;
  struct drm_device * dev;
  @@
  -list_for_each_entry(crtc,&dev->mode_config.crtc_list, head) {
  +for_each_crtc(dev,crtc) {
  	...
  }

Followed by a couple of fixups by hand (that spatch doesn't match the
cases where list_for_each_entry() is not followed by a set of '{', '}',
but I couldn't figure out a way to leave the '{' out of the iterator
match).
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Update to also fill in the new num_pipes field.

v3: Rebase on top of the pciid extraction.

v4: Switch from info->has*ring to info->ring mask. Also add VEBOX support whiel
at it.

v5: s/CHV_PCI_IDS/CHV_IDS/, and drop the trailing '\'
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add runtime PM support for VLV, but leave it disabled. The next patch
enables it.

The suspend/resume sequence used is based on [1] and [2]. In practice we
depend on the GT RC6 mechanism to save the HW context depending on the
render and media power wells. By the time we run the runtime suspend
callback the display side is also off and the HW context for that is
managed by the display power domain framework.

Besides the above there are Gunit registers that depend on a system-wide
power well. This power well goes off once the device enters any of the
S0i[R123] states. To handle this scenario, save/restore these Gunit
registers. Note that this is not the complete register set dictated by
[2], to remove some overhead, registers that are known not to be used are
ignored. Also some registers are fully setup by initialization functions
called during resume, these are not saved either. The list of registers
can be further reduced, see the TODO note in the code.

[1] VLV_gfx_clocking_PM_reset_y12w21d3 / "Driver D3 entry/exit"
[2] VLV2_S0IXRegs

v2:
- unchanged
v3:
- fix s/GEN6_PMIIR/GEN6_PMIMR/ typo when saving/restoring registers
  (Ville)
v4:
- rebased on the previous patch fixing GEN register prefixes
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[ rebased (according to v4) ]
Signed-off-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm, none of the RPM callbacks can fail, but the next patch adding
RPM support for VLV changes this, so prepare for it.

In case one of these callbacks return error RPM will get permanently
disabled until the error is explicitly cleared. In the future we could
add support for re-enabling it, for example after resetting the HW, but
for now - hopefully - we can live with the simpler solution.

v2:
- propagate the error from the resume callbacks too (Paulo)
v3:
- fix rebase fail typo around IS_GEN6() check in intel_runtime_suspend()
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

I've seen latencies up to 15msec, so increase the timeout to 20msec.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This will be needed by the VLV runtime PM helpers too, so factor it out.

Also add a safety check for the case where the previous force-off is
still pending, since I'm not sure if Punit can handle a new setting
while the previous one hasn't settled yet.

v2:
- unchanged
v3:
- add a note to the commit message about the safety check (Ville)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During runtime suspend there can be a last pending rps.work, so make
sure it's canceled. Note that in the runtime suspend callback we can't
get any RPS interrupts since it's called only after the GPU goes idle
and we set the minimum RPS frequency. The next possibility for an RPS
interrupt is only after getting an RPM ref (for example because of a new
GPU command) and calling the RPM resume callback.

v2:
- patch introduced in v2 of the patchset
v3:
- Change the order of canceling the rps.work and disabling interrupts to
  avoid the race between interrupt disabling and the the rps.work. Race
  spotted by Ville.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to re-init sizzling on all platforms so move it to the
platform independent runtime resume callback. The ring frequency reinit
is also needed everywhere except on VLV, but gen6_update_ring_freq()
will be a noop on VLV, so we can move this function too to platform
independent code.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is needed by the next patch moving the call out from platform
specific RPM callbacks to platform independent code.

No functional change.

v2:
- patch introduce in v2 of the patchset
v3:
- simplify platform check condition (Ville)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to disable the interrupts for all platforms, so make the helpers
for this platform independent and call them from them platform
independent runtime suspend/resume callbacks.

On HSW/BDW this will move interrupt disabling/re-enabling at the
beginning/end of runtime suspend/resume respectively, but I don't see
any reason why this would cause a problem there. In any case this seems
to be the correct thing to do even on those platforms.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On VLV we depend on RC6 to save the GT render and media HW context
before going to the D3 state via RPM, so as a preparation for the
VLV RPM support (added in an upcoming patch) disable RPM if RC6 is
disabled.

There is probably a similar dependency on other platforms too, so for
safety require RC6 for those too. For these platforms (SNB, HSW, BDW)
this is then a possible fix.

v2:
- require RC6 for all RPM platforms, not just for VLV (Paulo, Daniel)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

At least on VLV but probably on other platforms too we depend on RC6
being enabled for RPM, so disable RPM until the delayed RC6 enabling
completes.

v2:
- explain the reason for the _noresume version of RPM get (Daniel)
- use the simpler 'if (schedule_work()) rpm_get();' instead of
  'if (!cancel_work_sync()) rpm_get(); schedule_work();'
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Getting struct_mutex around the whole intel_enable_gt_powersave()
function is not necessary, since it's only needed for the ILK path
therein.

This will make intel_enable_gt_powersave() useable on the RPM resume
path for >=GEN6 (added in an upcoming patch to reset the RPS state
during RPM resume), where we can't (and need not) get this mutex.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Based on the hardware spec, the BDW GT3 machine has two independent
BSD ring that can be used to dispatch the video commands.
So just initialize it.

V3->V4: Follow Imre's comment to do some minor updates. For example:
more comments are added to describe the semaphore between ring.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
[danvet: Fix up checkpatch error.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Based on the hardware spec, the BDW GT3 has the different configuration
with the BDW GT1/GT2. So split the BDW device info definition.
This is to do the preparation for adding the Dual BSD rings on BDW GT3 machine.

V1->V2: Follow Daniel's comment to pay attention to the stolen check for BDW
in kernel/early-quirks.c
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During module load, if we fail to initialise the rings, we abort the
load reporting EIO. However during resume, even though we report EIO as
we fail to reinitialize the ringbuffers, the resume continues and the
device is restored - albeit in a non-functional state. As we cannot
execute any commands on the GPU, it is effectively wedged, mark it so.

As we now preserve the ringbuffers across resume, this should prevent
UXA from falling into the trap of repeatedly sending invalid
batchbuffers and dropping all further rendering into /dev/null.
Reported-and-tested-by: NJiri Kosina <jkosina@suse.cz>
References: https://bugs.freedesktop.org/show_bug.cgi?id=76554Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NOscar Mateo <oscar.mateo@intel.com>
[danvet: Drop unused error, spotted by Oscar.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Unfortunately this requires a drm-wide change, and I didn't see a sane
way around that. Luckily it's fairly simple, we just need to inline
the respective get_irq implementation from either drm_pci.c or
drm_platform.c.

With that we can now also remove drm_dev_to_irq from drm_irq.c.
Reviewed-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The dev->struct_mutex locking in drm_irq.c only protects
dev->irq_enabled. Which isn't really much at all and only prevents
especially nasty ums userspace from concurrently installing the
interrupt handling a few times. Or at least trying.

There are tons of unlocked readers of dev->irqs_enabled in the vblank
wait code (and by extension also in the pageflip code since that uses
the same vblank timestamp engine).

Real modesetting drivers should ensure that nothing can go haywire
with a sane setup teardown sequence. So we only really need this for
the drm_control ioctl, everywhere else this will just paper over
nastiness.

Note that drm/i915 is a bit specially due to the gem+ums combination.
So there we also need to properly protect the entervt and leavevt
ioctls. But it's definitely saner to do everything in one go than to
drop the lock in-between.

Finally there's the gpu reset code in drm/i915. That one's just race
(concurrent userspace calls to for vblank waits of pageflips could
spuriously fail). So wrap it up in with a nice comment since fixing
this is more involved.

v2: Rebase and fix commit message (Thierry)
Reviewed-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During resume the intel hda audio driver depends on the i915 driver
reinitializing the audio power domain. Since the order of calling the
i915 resume handler wrt. that of the audio driver is not guaranteed,
move the power domain reinitialization step to the resume_early
handler. This is guaranteed to run before the resume handler of any
other driver.

The power domain initialization in turn requires us to enable the i915
pci device first, so move that part earlier too.

Accordingly disabling of the i915 pci device should happen after the
audio suspend handler ran. So move the disabling later from the i915
resume handler to the resume_late handler.

v2:
- move intel_uncore_sanitize/early_sanitize earlier too, so they don't
  get reordered wrt. intel_power_domains_init_hw()

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76152Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NTakashi Iwai <tiwai@suse.de>
Cc: stable@vger.kernel.org
[danvet: Add cc: stable and loud comments that this is just a hack.]
[danvet: Fix "Should it be static?" sparse warning reported by Wu
Fengguang's kbuilder.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This sould be enough.

v2: BDW should also run hsw_runtime_resume (Ben).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that PC8 is part of runtime PM, the check is useless.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just because I have a SNB machine and I can easily test it.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We're adding runtime suspend support to more platforms, so organize
the code in a way that all a new platform needs to do is to add its
own gen-specific functions. Also rename the i915_ functions to intel_
to make it clear that it's the top level one, not something that just
runs on i915 platforms.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Remove the rest of the references to drm_i915_private_t. No functional
changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Drop hunk in i915_cmd_parser.c]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After we removed all the intermediate abstractions, we can rename
these functions to just hsw_{en,dis}able_pc8.

v2: - Rebase.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We already get runtime PM references, and PC8 is now part of runtime
PM, so this is enough.

v2: - Rebase.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently, when our driver becomes idle for i915.pc8_timeout (default:
5s) we enable PC8, so we save some power, but not everything we can.
Then, while PC8 is enabled, if we stay idle for more
autosuspend_delay_ms (default: 10s) we'll enter runtime PM and put the
graphics device in D3 state, saving even more power. The two features
are separate things with increasing levels of power savings, but if we
disable PC8 we'll never get into D3.

While from the modularity point of view it would be nice to keep these
features as separate, we have reasons to merge them:
 - We are not aware of anybody wanting a "PC8 without D3" environment.
 - If we keep both features as separate, we'll have to to test both
   PC8 and PC8+D3 code paths. We're already having a major pain to
   make QA do automated testing of just one thing, testing both paths
   will cost even more.
 - Only Haswell+ supports PC8, so if we want to add runtime PM support
   to, for example, IVB, we'll have to copy some code from the PC8
   feature to runtime PM, so merging both features as a single thing
   will make it easier for enabling runtime PM on other platforms.

This patch only does the very basic steps required to have PC8 and
runtime PM merged on a single feature: the next patches will take care
of cleaning up everything.

v2: - Rebase.
v3: - Rebase.
    - Fully remove the deprecated i915 params since Daniel doesn't
      consider them as part of the ABI.
v4: - Rebase.
    - Fix typo in the commit message.
v5: - Rebase, again.
    - Add a huge comment explaining the different forcewake usage
      (Chris, Daniel).
    - Use open-coded forcewake functions (Daniel).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we regularly defer the forcewake dance to a timer func, it is
likely to fire after we disable the device during suspend. This
generates an oops as we detect inconsistency in the hardware state. So
before suspend, we want to complete the outstanding dance and generally
sanitize the registers before handing back to the BIOS.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

BDW is no longer flagged as preliminary hw, but without
i915.preliminary_hw_support module param set the logs are filled with
WARNs about it.

Just make semaphores off the BDW per-chip default for now.

CC: Ben Widawsky <ben@bwidawsk.net>
Reported-by: NSebastien Dufour <sebastien.dufour@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For example if we get bug reports with similar error states and
suspend count is always 1, that might lead the Sherlocks to
right general direction.
Suggested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Just to be sure...
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This got lost when we shuffled around our internal branch and
GEN7_FEATURES macro. There were no HW changes to support FBC, so we just
need to set the flag.

v2: Don't allow FBC for any pipe but A on platforms with DDI. (Paulo)

Cc: Daisy Sun <daisy.sun@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The power domains framework is internal to the i915 driver, so pass
drm_i915_private instead of drm_device to its functions.

Also remove a dangling intel_set_power_well() declaration.

No functional change.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

pci_get_class(class, from) drops the refcount for 'from', so the
extra pci_dev_put we do on it will result in a use after free bug
starting with the WARN below.

Regression introduced in

commit 6a9c4b35
Author: Rui Guo <firemeteor@users.sourceforge.net>
Date:   Wed Jun 19 21:10:23 2013 +0800

    drm/i915: Fix PCH detect with multiple ISA bridges in VM

[  164.338460] WARNING: CPU: 1 PID: 2094 at include/linux/kref.h:47 klist_next+0xae/0x110()
[  164.347731] CPU: 1 PID: 2094 Comm: modprobe Tainted: G           O 3.13.0-imre+ #354
[  164.356468] Hardware name: Intel Corp. VALLEYVIEW B0 PLATFORM/NOTEBOOK, BIOS BYTICRB1.X64.0062.R70.1310112051 10/11/2013
[  164.368796] Call Trace:
[  164.371609]  [<ffffffff816a32a6>] dump_stack+0x4e/0x7a
[  164.377447]  [<ffffffff8104f75d>] warn_slowpath_common+0x7d/0xa0
[  164.384238]  [<ffffffff8104f83a>] warn_slowpath_null+0x1a/0x20
[  164.390851]  [<ffffffff8169aeae>] klist_next+0xae/0x110
[  164.396777]  [<ffffffff8130a110>] ? pci_do_find_bus+0x70/0x70
[  164.403286]  [<ffffffff813cb4a9>] bus_find_device+0x89/0xc0
[  164.409719]  [<ffffffff8130a373>] pci_get_dev_by_id+0x63/0xa0
[  164.416238]  [<ffffffff8130a4e4>] pci_get_class+0x44/0x50
[  164.422433]  [<ffffffffa034821f>] intel_dsm_detect+0x16f/0x1f0 [i915]
[  164.429801]  [<ffffffffa03482ae>] intel_register_dsm_handler+0xe/0x10 [i915]
[  164.437831]  [<ffffffffa02d30fe>] i915_driver_load+0xafe/0xf30 [i915]
[  164.445126]  [<ffffffff8158a150>] ? intel_alloc_coherent+0x110/0x110
[  164.452340]  [<ffffffffa0148c07>] drm_dev_register+0xc7/0x150 [drm]
[  164.459462]  [<ffffffffa014b23f>] drm_get_pci_dev+0x11f/0x1f0 [drm]
[  164.466554]  [<ffffffff816abb81>] ? _raw_spin_unlock_irqrestore+0x51/0x70
[  164.474287]  [<ffffffffa02cf7a6>] i915_pci_probe+0x56/0x60 [i915]
[  164.481185]  [<ffffffff8130a028>] pci_device_probe+0x78/0xf0
[  164.487603]  [<ffffffff813cd495>] driver_probe_device+0x155/0x350
[  164.494505]  [<ffffffff813cd74e>] __driver_attach+0x6e/0xa0
[  164.500826]  [<ffffffff813cd6e0>] ? __device_attach+0x50/0x50
[  164.507333]  [<ffffffff813cb2be>] bus_for_each_dev+0x6e/0xc0
[  164.513752]  [<ffffffff813ccefe>] driver_attach+0x1e/0x20
[  164.519870]  [<ffffffff813cc958>] bus_add_driver+0x138/0x260
[  164.526289]  [<ffffffffa0188000>] ? 0xffffffffa0187fff
[  164.532116]  [<ffffffff813cde78>] driver_register+0x98/0xe0
[  164.538558]  [<ffffffffa0188000>] ? 0xffffffffa0187fff
[  164.544389]  [<ffffffff813087b0>] __pci_register_driver+0x60/0x70
[  164.551336]  [<ffffffffa014b37d>] drm_pci_init+0x6d/0x120 [drm]
[  164.558040]  [<ffffffffa0188000>] ? 0xffffffffa0187fff
[  164.563928]  [<ffffffffa018806a>] i915_init+0x6a/0x6c [i915]
[  164.570363]  [<ffffffff810002da>] do_one_initcall+0xaa/0x160
[  164.576783]  [<ffffffff8103b140>] ? set_memory_nx+0x40/0x50
[  164.583100]  [<ffffffff810ce7f5>] load_module+0x1fb5/0x2550
[  164.589410]  [<ffffffff810caab0>] ? store_uevent+0x40/0x40
[  164.595628]  [<ffffffff810cee7d>] SyS_init_module+0xed/0x100
[  164.602048]  [<ffffffff816b3c52>] system_call_fastpath+0x16/0x1b

v2: simplify the loop further (Chris)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reported-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65652
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74161Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

A check of rps/rc6 state after i915_reset determined that the ring
MAX_IDLE registers were returned to their hardware defaults and that
the GEN6_PMIMR register was set to mask all interrupts. This change
restores those values to their pre-reset states by re-initializing
rps/rc6 in i915_reset. A full re-initialization was opted for versus
a targeted set of restore operations for simplicity and maintain-
ability. Note that the re-initialization is not done for Ironlake,
due to a past comment that it causes problems.

Also updated the rps initialization sequence to preserve existing
min/max values in the case of a re-init. We assume the values were
validated upon being set and do not do further range checking. The
debugfs interface for changing min/max was updated with range
checking to ensure this condition (already present in sysfs
interface).

v2: fix rps logging to output hw_max and hw_min, not rps.max_delay
    and rps.min_delay which don't strictly represent hardware limits.
    Add igt testcase to signed-off-by section.

Testcase: igt/pm_rps/reset
Signed-off-by: NJeff McGee <jeff.mcgee@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>