Needed by the VLV S0ix context save/restore helpers.

v2:
- unchanged
v3:
- use proper GEN register prefixes (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>

Due to Pipe C DPINVGTT has more bits on CHV.

v2: Fix comment to say VLV/CHV (Rafael)
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Rebase on top of Ben's GT interrupt shuffling.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

CHV has pipe C and PSR which cause changes to DPFLIPSTAT.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

FIXME: We probably want to sprinkle _CHV suffixes over these.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Enable aliasing PPGTT for CHV, but keep full PPGTT still disabled until
it gets enabled for BDW.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Page table updates were getting stuck in the CPU cache on chv causing
spurious page faults and strange behaviour.
Signed-off-by: NRafael Barbalho <rafael.barbalho@intel.com>
[vsyrjala: Add !HAS_LLC checks]
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Ignore the cache bits in PPAT and just set the snoop bit where
appropriate. BDW WB is mapped to snooped access, while all other
modes are mapped to non-snooped access.

The hardware supposedly ignores everything except the snoop bit
in the PPAT entries.

Additionally the hardware actually enforces snooping for all
page table accesses, and thus the snoop bit is ignored for PDEs.

v2: Rebased on top of the bdw resume fix to reload the ppat entries.

v3: Rebase on top of the i915_gem_gtt.h header extraction.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
Acked-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We won't be calling intel_enable_primary_plane() or
intel_disable_primary_plane() with the primary plane in the
wrong state. So remove the useless DISPLAY_PLANE_ENABLE checks.

v2: Convert the checks to WARNs instead (Daniel,Paulo)
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On ILK when we disable a particular watermark level, we must
maintain the actual watermark values for that level for some time
(until the next vblank possibly). Otherwise we risk underruns.

In order to achieve that result we must merge the LP1+ watermarks a
bit differently since we must also merge levels that are to be
disabled. We must also make sure we don't overflow the fields in the
watermark registers in case the calculated watermarks come out too
big to fit.

As early as possbile we mark all computed watermark levels as
disabled if they would exceed the register maximums. We make sure
to leave the actual watermarks for such levels zeroed out. Then during
merging, we take the maxium values for every level, regardless if
they're disabled or not. That may seem a bit pointless since at the
moment all the watermark levels we merge should have their values
zeroed if the level is already disabled. However soon we will be
dealing with intermediate watermarks that, in addition to the new
watermark values, also contain the previous watermark values, and so
levels that are disabled may no longer be zeroed out.

v2: Split the patch in two (Paulo)
    Use if() instead of & when merging ->enable (Paulo)
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Fix commit message as noted by Paulo.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When we calculate the watermarks for a pipe make sure we leave any
level fully zeroed out if it would exceed any of the maximum values
that fit in the registers.

This will be important later when we start to use also disabled
watermark levels during LP1+ merging.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add trace points for observing the atomic pipe update mechanism.

v2: Rebased due to earlier changes
v3: Pass intel_crtc instead of drm_crtc (Daniel)
v4: Pass frame counter from the caller to evaded/end since
    the caller now always has that ready
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Move the primary plane enable/disable to occur atomically with the
sprite update that caused the primary plane visibility to change.

FBC and IPS enable/disable is left to happen well before or after
the primary plane change.

v2: Pass intel_crtc instead of drm_crtc (Daniel)
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add a mechanism by which we can evade the leading edge of vblank. This
guarantees that no two sprite register writes will straddle on either
side of the vblank start, and that means all the writes will be latched
together in one atomic operation.

We do the vblank evade by checking the scanline counter, and if it's too
close to the start of vblank (too close has been hardcoded to 100usec
for now), we will wait for the vblank start to pass. In order to
eliminate random delayes from the rest of the system, we operate with
interrupts disabled, except when waiting for the vblank obviously.

Note that we now go digging through pipe_to_crtc_mapping[] in the
vblank interrupt handler, which is a bit dangerous since we set up
interrupts before the crtcs. However in this case since it's the vblank
interrupt, we don't actually unmask it until some piece of code
requests it.

v2: preempt_check_resched() calls after local_irq_enable() (Jesse)
    Hook up the vblank irq stuff on BDW as well
v3: Pass intel_crtc instead of drm_crtc (Daniel)
    Warn if crtc.mutex isn't locked (Daniel)
    Add an explicit compiler barrier and document the barriers (Daniel)
    Note the irq vs. modeset setup madness in the commit message (Daniel)
v4: Use prepare_to_wait() & co. directly and eliminate vbl_received
v5: Refactor intel_pipe_handle_vblank() vs. drm_handle_vblank() (Chris)
    Check for min/max scanline <= 0 (Chris)
    Don't call intel_pipe_update_end() if start failed totally (Chris)
    Check that the vblank counters match on both sides of the critical
    section (Chris)
v6: Fix atomic update for interlaced modes
v7: Reorder code for better readability (Chris)
v8: Drop preempt_check_resched(). It's not available to modules
    anymore and isn't even needed unless we ourselves cause
    a wakeup needing reschedule while interrupts are off
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

All the rest of the code to enable this is in my branch. Without my
branch, hitting > 32b offsets is impossible. The code has always
"supported" 64b, but it's never actually been run of tested. This change
doesn't actually fix anything. [1] I am not sure why X won't work yet. I
do not get hangs or obvious errors.

There are 3 fixes grouped together here. First is to remove the
hardcoded 0 for the upper dword of the relocation. The next fix is to
use a 64b value for target_offset. The final fix is to not directly
apply target_offset to reloc->delta. reloc->delta is part of ABI, and so
we cannot change it. As it stands, 32b is enough to represent everything
we're interested in representing anyway. The main problem is, we cannot
add greater than 32b values to it directly.

[1] Almost all of intel-gpu-tools is not yet ready to test 64b
relocations. There are a few places that expect 32b values for offsets
and these all won't work.

Cc: Rafael Barbalho <rafael.barbalho@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Previously, our code only had a 32b offset value for where the
batchbuffer starts. With full PPGTT, and 64b canonical GPU address
space, that is an insufficient value. The code to expand is pretty
straight forward, and only one platform needs to do anything with the
extra bits.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

SDVO is used by both crtcs using the i9xx_ and the ironlake_
functions. For both cases there is nothing between the
encoder->mode_set and the encoder->pre_enable calls that touches the
hardware.

The vlv_ functions are different since they enable the pll before the
->pre_enable hook. But SDVO isn't supported on vlv platforms, so this
doesn't matter.

We've also already clean up all the sdvo state computation logic, all
relevant parts are already in the ->compute_config hook.  So we can
just get rid of the ->mode_set hook by converting it to a ->pre_enable
hook.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We only set a few bits in the ADPA register, which we then read back
in the enable/disable hooks. So we can just move that bit of state
computation code to the place where we need it since setting these
bits without enabling the CRT encoder has no effects.

The only exceptions are the hotplug bits since they affect the hotplug
detection logic, but we already set those in the ->reset function and
then never touch them.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently for the i9xx crtc hooks there's nothing between the call to
encoder->mode_set and encoder->pre_enable which touches the hardware.

Therefore, since tv is only used on gen3/4, we can just move the hook.
Yay for easy cases!

The only other important thing to check is that the new
->pre_enable hook is idempotent wrt the sw state since now it can
be called multiple times (due to DPMS). After a the bit of refactoring
this is now easy to check: It only reads crtc->config and computes
derived state but otherwise leaves it as-is, so we're good.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The pipe and plane _are_ disabled when we call this. So replace it
all with the corresponding assert (as self-documenting code) and
rip out all the lore.

Checking for a disabled plane would require us to export those macros
from intel_display.c, but if the pipe is off the plane isn't working
either. So this single check is good enough.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We only support TV-out on gen3/4 mobile platforms, and i915gm is the
only one that matches.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

intel_tv_mode_set is still too bug.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

intel_tv_mode_set is just too big.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently for the i9xx crtc hooks there's nothing between the call to
encoder->mode_set and encoder->pre_enable which touches the hardware.

Therefore, since dvo is only used on gen2, we can just move the hook.
Yay for easy cases!

The only other important thing to check is that the new
->pre_enable hook is idempotent wrt the sw state since now it can be
called multiple times (due to DPMS). It only reads crtc->config but
otherwise leaves it as-is, so we're good.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For a bunch of reasons we want to move away from the ->mode_set
callbacks: All hw state setup needs to move into ->enable hooks (so
that DOMS can do runtime pm) and all the configuration setup needs to
move into the compute_config functions.

To start with this make the enocer->mode_set callback optional.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The BIOS can enable a pipe but leave the primary plane disabled. This
coflicts with out current idea of primary_enabled. Read the actual
hardware plane state and set primary_enabled appropriately.

We currently assume that primary_enabled is always true when we're about
to disable a crtc. That needs to change now as the plane may not be
enabled. So replace the relevant WARNs with early returns in
intel_{enable,disable}_primary_hw_plane().

Fixes the following warning
[    3.831602] WARNING: CPU: 0 PID: 1112 at linux/drivers/gpu/drm/i915/intel_display.c:1918 intel_disable_primary_hw_plane+0xe4/0xf0 [i915]()

which got introduced here by me:
 commit e9e39655c0c30cddc3f8c09a757678a24dd36737
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Mon Apr 28 15:53:25 2014 +0300

    drm/i915: Remove useless checks from primary enable/disable
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add_request has always contained both the semaphore mailbox updates as
well as the breadcrumb writes. Since the semaphore signal is the one
which actually knows about the number of dwords it needs to emit to the
ring, we move the ring_begin to that function. This allows us to remove
the hideously shared #define

On a related not, gen8 will use a different number of dwords for
semaphores, but not for add request.

v2: Make number of dwords an explicit part of signalling (via function
argument). (Chris)

v3: very slight comment change
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 abstraction again is in preparation for gen8. Gen8 will bring new
semantics for doing this operation.

While here, make the writes of MI_NOOPs explicit for non-existent rings.
This should have been implicit before.

NOTE: This is going to be removed in a few patches.
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 will be helpful in abstracting some of the code in preparation for
gen8 semaphores.

v2: Move mbox stuff to a separate struct

v3: Rebased over VCS2 work

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During the initial power well enabling on the driver init/resume path
we can avoid initialzing part of the HW/SW state that will be
initialized anyway by the subsequent init/resume code. For some steps
like HPD initialization this redundancy is not only an overhead but an
actual problem, since they can't be run this early in the overall init
sequence.

Add a flag marking the init phase and skip reinitialzing state that is
not strictly necessary based on that.

This is also needed by the upcoming HPD init restructuring by Thierry
and Daniel.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In commit 691e6415
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Apr 9 09:07:36 2014 +0100

    drm/i915: Always use kref tracking for all contexts.

we populated fake contexts on all platforms. These were identical to the
full hardware context tracking structs, except for the ctx->obj used to
store the hardware state. However, there remained one place where we
assumed that if a context existed, it would have an object associated
with it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77717
Testcase: igt/drv_suspend/debugfs-reader
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add a new function intel_get_crtc_scanline() that returns the current
scanline counter for the crtc.

v2: Rebase after vblank timestamp changes.
    Use intel_ prefix instead of i915_ as is more customary for
    display related functions.
    Include DRM_SCANOUTPOS_INVBL in the return value even w/o
    adjustments, for a bit of extra consistency.
v3: Change the implementation to be based on DSL on all gens,
    since that's enough for the needs of atomic updates, and
    it will avoid complicating the scanout position calculations
    for the vblank timestamps
v4: Don't break scanline wraparound for interlaced modes
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Seems I've been a bit dense with regards to the start of vblank
vs. the scanline counter / pixel counter.

After staring at the pixel counter on gen4 I came to the conclusion
that the start of vblank interrupt and scanline counter increment
happen at the same time. The scanline counter increment is documented
to occur at start of hsync, which means that the start of vblank
interrupt must also trigger there. Looking at the pixel counter value
when the scanline wraps from vtotal-1 to 0 confirms that, as the pixel
counter at that point reads hsync_start. This also clarifies why we see
need the +1 adjustment to the scaline counter. The counter actually
starts counting from vtotal-1 on the first active line.

I also confirmed that the frame start interrupt happens ~1 line after
the start of vblank, but the frame start occurs at hblank_start instead.
We only use the frame start interrupt on gen2 where the start of vblank
interrupt isn't available. The only important thing to note here is that
frame start occurs after vblank start, so we don't have to play any
additional tricks to fix up the scanline counter.

The other thing to note is the fact that the pixel counter on gen3-4
starts counting from the start of horizontal active on the first active
line. That means that when we get the start of vblank interrupt, the
pixel counter reads (htotal*(vblank_start-1)+hsync_start). Since we
consider vblank to start at (htotal*vblank_start) we need to add a
constant (htotal-hsync_start) offset to the pixel counter, or else we
risk misdetecting whether we're in vblank or not.

I talked a bit with Art Runyan about these topics, and he confirmed my
findings. And that the same rules should hold for platforms which don't
have the pixel counter. That's good since without the pixel counter it's
rather difficult to verify the timings to this accuracy.

So the conclusion is that we can throw away all the ISR tricks I added,
and just increment the scanline counter by one always.
Reviewed-by: NSourab Gupta <sourabgupta@gmail.com>
Reviewed-by: NAkash Goel <akash.goels@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It seems we need this at least for the current platforms we have, but
probably not later. In any event, it should cause too much harm as we do
the same thing on several other platforms.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The same register exists for querying and programming eDRAM AKA eLLC. So
we can simply use it. For now, use all the same defaults as we had
for Haswell, since like Haswell, I have no further details.

I do not actually have a part with eDRAM, so I cannot test this.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

I don't have any insight on what parts can do what. The docs do seem to
suggest WT caching works in at least the same manner as it does on
Haswell.

The addr = 0  is to shut up GCC:
drivers/gpu/drm/i915/i915_gem_gtt.c:80:7: warning: 'addr' may be used
uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On BDW we don't enable RC6 at the moment, but this isn't reflected in
the (sanitized) i915.enable_rc6 option. So make enable_rc6 report
correctly that RC6 is disabled, which will also effectively disable RPM
on BDW (since RPM depends on RC6).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77565Signed-off-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

assert_plane_enabled() is now triggering during FDI link train because
we no longer enable planes that early.

This problem got introduced in:
 commit a5c4d7bc
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Fri Mar 7 18:32:13 2014 +0200

    drm/i915: Disable/enable planes as the first/last thing during modeset on ILK+

Just drop the assert since we shouldn't need planes for link training.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Squash in fixup for now unused plane local variable, reported
by 0-day tester.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 60f2b4af.

The same warning has been fixed in e5081a53 and
these two commits got merged in 74e99a84de2d0980320612db8015ba606af42114 which
caused another warning. Simply, the reverted commit casted the pointer
difference to unsigned long and the other commit changed the output type from
long to ptrdiff_t.

The other commit fixes the original warning the better way so I'm reverting
this commit now.
Signed-off-by: NJan Moskyto Matejka <mq@suse.cz>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have a struct_mutex deadlock during driver init on ILK

[   54.320273] =============================================
[   54.320371] [ INFO: possible recursive locking detected ]
[   54.320471] 3.15.0-rc2-flip_race+ #2 Not tainted
[   54.320567] ---------------------------------------------
[   54.320665] modprobe/2178 is trying to acquire lock:
[   54.320762]  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa0568b05>] intel_enable_gt_powersave+0xa5/0x9d0 [i915]
[   54.321111]
[   54.321111] but task is already holding lock:
[   54.321250]  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa05b4c2e>] intel_modeset_init_hw+0x3e/0x60 [i915]
[   54.321583]
[   54.321583] other info that might help us debug this:
[   54.321724]  Possible unsafe locking scenario:
[   54.321724]
[   54.321863]        CPU0
[   54.321954]        ----
[   54.322046]   lock(&dev->struct_mutex);
[   54.322221]   lock(&dev->struct_mutex);
[   54.322397]
[   54.322397]  *** DEADLOCK ***
[   54.322397]
[   54.322638]  May be due to missing lock nesting notation
[   54.322638]
[   54.322781] 4 locks held by modprobe/2178:
[   54.322875]  #0:  (&dev->mutex){......}, at: [<ffffffff813592eb>] __driver_attach+0x5b/0xb0
[   54.323230]  #1:  (&dev->mutex){......}, at: [<ffffffff813592f9>] __driver_attach+0x69/0xb0
[   54.323582]  #2:  (drm_global_mutex){+.+.+.}, at: [<ffffffffa04e1e0d>] drm_dev_register+0x2d/0x120 [drm]
[   54.323945]  #3:  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa05b4c2e>] intel_modeset_init_hw+0x3e/0x60 [i915]

This regression got introduced in:
 commit 586d5270b60dc1f35cc3ca982d403765bad77965
 Author: Imre Deak <imre.deak@intel.com>
 Date:   Mon Apr 14 20:24:28 2014 +0300

    drm/i915: move getting struct_mutex lower in the callstack during GPU reset

Fix the problem by not taking struct_mutex around intel_enable_gt_powersave()
in intel_modeset_init_hw() since intel_enable_gt_powersave() now grabs the
mutex itself.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>