Since 9eb1e57f
drm/dp/mst: make sure mst_primary mstb is valid in work function

we validate the mstb structs in the work function, and doing
that takes a reference. So we should never get here with the
work function running using the mstb device, only if the work
function hasn't run yet or is running for another mstb.

So we don't need to sync the work here, this was causing
lockdep spew as below.

[  +0.000160] =============================================
[  +0.000001] [ INFO: possible recursive locking detected ]
[  +0.000002] 3.10.0-320.el7.rhel72.stable.backport.3.x86_64.debug #1 Tainted: G        W      ------------
[  +0.000001] ---------------------------------------------
[  +0.000001] kworker/4:2/1262 is trying to acquire lock:
[  +0.000001]  ((&mgr->work)){+.+.+.}, at: [<ffffffff810b29a5>] flush_work+0x5/0x2e0
[  +0.000007]
but task is already holding lock:
[  +0.000001]  ((&mgr->work)){+.+.+.}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710
[  +0.000004]
other info that might help us debug this:
[  +0.000001]  Possible unsafe locking scenario:

[  +0.000002]        CPU0
[  +0.000000]        ----
[  +0.000001]   lock((&mgr->work));
[  +0.000002]   lock((&mgr->work));
[  +0.000001]
 *** DEADLOCK ***

[  +0.000001]  May be due to missing lock nesting notation

[  +0.000002] 2 locks held by kworker/4:2/1262:
[  +0.000001]  #0:  (events_long){.+.+.+}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710
[  +0.000004]  #1:  ((&mgr->work)){+.+.+.}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710
[  +0.000003]
stack backtrace:
[  +0.000003] CPU: 4 PID: 1262 Comm: kworker/4:2 Tainted: G        W      ------------   3.10.0-320.el7.rhel72.stable.backport.3.x86_64.debug #1
[  +0.000001] Hardware name: LENOVO 20EGS0R600/20EGS0R600, BIOS GNET71WW (2.19 ) 02/05/2015
[  +0.000008] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
[  +0.000001]  ffffffff82c26c90 00000000a527b914 ffff88046399bae8 ffffffff816fe04d
[  +0.000004]  ffff88046399bb58 ffffffff8110f47f ffff880461438000 0001009b840fc003
[  +0.000002]  ffff880461438a98 0000000000000000 0000000804dc26e1 ffffffff824a2c00
[  +0.000003] Call Trace:
[  +0.000004]  [<ffffffff816fe04d>] dump_stack+0x19/0x1b
[  +0.000004]  [<ffffffff8110f47f>] __lock_acquire+0x115f/0x1250
[  +0.000002]  [<ffffffff8110fd49>] lock_acquire+0x99/0x1e0
[  +0.000002]  [<ffffffff810b29a5>] ? flush_work+0x5/0x2e0
[  +0.000002]  [<ffffffff810b29ee>] flush_work+0x4e/0x2e0
[  +0.000002]  [<ffffffff810b29a5>] ? flush_work+0x5/0x2e0
[  +0.000004]  [<ffffffff81025905>] ? native_sched_clock+0x35/0x80
[  +0.000002]  [<ffffffff81025959>] ? sched_clock+0x9/0x10
[  +0.000002]  [<ffffffff810da1f5>] ? local_clock+0x25/0x30
[  +0.000002]  [<ffffffff8110dca9>] ? mark_held_locks+0xb9/0x140
[  +0.000003]  [<ffffffff810b4ed5>] ? __cancel_work_timer+0x95/0x160
[  +0.000002]  [<ffffffff810b4ee8>] __cancel_work_timer+0xa8/0x160
[  +0.000002]  [<ffffffff810b4fb0>] cancel_work_sync+0x10/0x20
[  +0.000007]  [<ffffffffa0160d17>] drm_dp_destroy_mst_branch_device+0x27/0x120 [drm_kms_helper]
[  +0.000006]  [<ffffffffa0163968>] drm_dp_mst_link_probe_work+0x78/0xa0 [drm_kms_helper]
[  +0.000002]  [<ffffffff810b5850>] process_one_work+0x220/0x710
[  +0.000002]  [<ffffffff810b57e4>] ? process_one_work+0x1b4/0x710
[  +0.000005]  [<ffffffff810b5e5b>] worker_thread+0x11b/0x3a0
[  +0.000003]  [<ffffffff810b5d40>] ? process_one_work+0x710/0x710
[  +0.000002]  [<ffffffff810beced>] kthread+0xed/0x100
[  +0.000003]  [<ffffffff810bec00>] ? insert_kthread_work+0x80/0x80
[  +0.000003]  [<ffffffff817121d8>] ret_from_fork+0x58/0x90

v2: add flush_work.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

In order to cache the EDID properly for tiled displays, we
need to retrieve it before we register the connector with
userspace, otherwise userspace can call get resources
and try and get the edid before we've even cached it.

This fixes some problems when hotplugging mst monitors,
with X/mutter running. As mutter seems to get 0 modes
for one of the monitors in the tile.

v2: fix warning in radeon
handle tile setting in cached path rather than
get edid path.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

Update the state before sending the msg to close it.

v2: reset value if return indicates we haven't send the msg.
v3: just clean the code up.
Pointed out by Adam J Richter on

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91481Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

output ports should always have a connector, unless
in the rare case connector allocation fails in the
driver.

In this case we only need to teardown the pdt,
and free the struct, and there is no need to
send a hotplug msg.

In the case were we add the port to the destroy
list we need to send a hotplug if we destroy
any connectors, so userspace knows to reprobe
stuff.

this patch also handles port->connector allocation
failing which should be a rare event, but makes
the code consistent.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

This is unnecessary and it makes it easier to see what is needed
from port.

also add blank line to make things nicer.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

It was just a wrapper around drm_fb_helper_set_par that
called cursor_set2 in addition.  Now that the core handles
this, drop this radeon specific version.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

If a driver uses the cursor_set2 crtc callback rather than
cursor_set, use that.  This fixes the fbdev helper for drivers
that use cursor_set2.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

a few i915 fixes for v4.3.

* tag 'drm-intel-fixes-2015-10-01' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Call non-locking version of drm_kms_helper_poll_enable(), v2
  drm: Add a non-locking version of drm_kms_helper_poll_enable(), v2
  drm/i915: Consider HW CSB write pointer before resetting the sw read pointer
  drm/i915/skl: Don't call intel_prepare_ddi when encoder list isn't yet initialized.

A single commit to fix a command submission hang regression.

Pull request of 2015-10-01

* tag 'vmwgfx-fixes-4.3-151001' of git://people.freedesktop.org/~thomash/linux:
  drm/vmwgfx: Fix a command submission hang regression

Merge branch 'exynos-drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-fixes

   This pull request includes regression fixups, build warnings, and
   trivial cleanups which mostly remove some codes not used anymore.

* 'exynos-drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos:
  drm/exynos: Staticize local function in exynos_drm_gem.c
  drm/exynos: fimd: actually disable dp clock
  drm/exynos: dp: remove suspend/resume functions
  drm/exynos: remove unused mode_fixup() code
  drm/exynos: remove decon_mode_fixup()
  drm/exynos: remove fimd_mode_fixup()
  drm/exynos: rotator: Clock control is unused if !PM
  drm/exynos: fimc: Clock control is unused if !PM
  drm/exynos: Suspend/resume is unused if !PM
  drm/exynos: create a fake mmap offset with gem creation
  drm/exynos: remove call to drm_gem_free_mmap_offset()
  drm/exynos: Remove useless EXPORT_SYMBOL_GPLs
  drm/exynos: cleanup line feed in exynos_drm_gem_get_ioctl
  drm/exynos: cleanup function calling written twice
  drm/exynos: staticize exynos_drm_gem_init()
  drm/exynos: remove unnecessary NULL assignment
  drm/exynos: fix missed calling of drm_prime_gem_destroy()
  drm/exynos: fix layering violation of address

radeon and amdgpu fixes for 4.3.
- backlight s/r fixes
- typo fix from Dan
- vm debugging fix
- remove import_gpu_mem after discussion with Daniel

* 'drm-fixes-4.3' of git://people.freedesktop.org/~agd5f/linux:
  drm/amdgpu: only print meaningful VM faults
  drm/amdgpu/cgs: remove import_gpu_mem
  drm/amdgpu:  Restore LCD backlight level on resume
  drm/radeon: Restore LCD backlight level on resume (>= R5xx)
  drm/amdgpu: signedness bug in amdgpu_cs_parser_init()

The exynos_drm_gem_mmap_buffer() is not used outside so make it static.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

fimd_dp_clock_enable() was setting the always to enabled,
this patch fix this to actually use the value that is set to 'val'.
Reported-by: NEmilio López <emilio.lopez@collabora.co.uk>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

This patch removes unnecessary pm suspend/resume functions.

All kms sub drivers will be controlled by top of Exynos drm driver
and connector dpms so these sub drivers shouldn't have their own
pm interfaces.
Signed-off-by: NInki Dae <inki.dae@samsung.com>
Reviewed-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

When disabling/enabling a crtc the primary area must be updated
independently of which crtc has been disabled/enabled.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1264735Signed-off-by: NFabiano Fidêncio <fidencio@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

Port of radeon commit 9b7d786b.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>

It was added for completeness, but we don't have any users
for it yet.  Daniel noted that it may be racy. Remove it.

Change-Id: I5f5546f8911a4f294008a62dc86a73f3face38d1
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drm_kms_helper_poll_enable() is called from a context in
intel_hpd_irq_storm_disable() where the the mode_config mutex is
already locked.
When this function was converted to lock this mutex in
commit 8c4ccc4a ("drm/probe-helper: Grab mode_config.mutex
in poll_init/enable") a deadlock occurred.
Call the newly implemented non-locking version of this function.

Changes since v1:
- use function name suffix '_locked' for the function that
  is to be called from a locked context.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

drm_kms_helper_poll_enable() was converted to lock the mode_config
mutex in commit 8c4ccc4a
("drm/probe-helper: Grab mode_config.mutex in poll_init/enable").

This disregarded the cases where this function is called from a context
where this mutex is already locked.

Add a non-locking version as well.

Changes since v1:
- use function name suffix '_locked' for the function that
  is to be called from a locked context.
Signed-off-by: NEgbert Eich <eich@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

When we're out of command buffer space, we turn on the command buffer
processed irq without re-checking for finished command buffers afterwards.
This might lead to a missed irq and the command submission process waiting
forever for space.

Fix this by rerunning the command buffer submission handler whenever we're
out of command space. This ensures both that we don't needlessly turn on
the irq, and that if we decide to turn on the irq, we recheck for finished
command buffers before going to sleep.
Reported-and-tested-by: NBryan Li <ldexin@vmware.com>
Signed-off-by: NThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: NSinclair Yeh <syeh@vmware.com>

CRTC's mode_fixup() isn't used anymore in exynos, remove it.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The only thing mode_fixup was doing was set the adjusted_mode->vrefresh to
60, but it already has the value of 60 when the decon_mode_fixup() is
called. That means this call is actually pointless and can be removed.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The only thing mode_fixup was doing was set the adjusted_mode->vrefresh to
60, but it already has the value of 60 when the fimd_mode_fixup() is
called. That means this call is actually pointless and can be removed.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

Protect the rotator_clk_crtl() function with an #ifdef CONFIG_PM guard
to avoid "defined but not used" warnings.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

Protect the fimc_clk_ctrl() function with an #ifdef CONFIG_PM guard to
avoid "defined but not used" warnings.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

Protect the suspend and resume callbacks with an #ifdef CONFIG_PM_SLEEP
guard to avoid "defined but not used" warnings.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

Don't create a fake mmap offset in exynos_drm_gem_dumb_map_offset. If
not, it will call drm_gem_create_mmap_offset whenever user requests
DRM_IOCTL_MODE_MAP_DUMB ioctl.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The drm_gem_object_release() function already performs this cleanup,
so there is no reason to do it explicitly.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

All the user of these functions are inside exynos-drm driver and
you don't need to export the symbols for that case.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The beginning of statement in function is next line of a brace.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

By if statment, some function callings are written twice. It needs
several line feed by indentation in if statment. Make to one function
calling from outside if statment.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The exynos_drm_gem_init() is used only in exynos_drm_gem.c file. Make it
static and don't export it.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

They will be freed right or was freed already, so NULL assignment is
unnecessary.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

When obj->import_attach is existed, code calling drm_prime_gem_destroy()
was removed from commit 67e93c80 ("drm/exynos: stop copying sg
table"), and it's a fault.

The drm_prime_gem_destroy() is cleanup function which GEM drivers need
to call when they use drm_gem_prime_import() to import dma-bufs, so
exynos-drm driver using drm_gem_prime_import() needs calling
drm_prime_gem_destroy().
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

There is no guarantee that DMA addresses are the same as physical
addresses, but dma_to_pfn() knows how to convert a dma_addr_t to a PFN
which can then be converted to a struct page.
Suggested-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

Instead of only enabling the backlight (which seems to set it to max
brightness), just re-set the current backlight level, which also takes
care of enabling the backlight if necessary.

Port of radeon commit:
drm/radeon: Restore LCD backlight level on resume (>= R5xx)
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Instead of only enabling the backlight (which seems to set it to max
brightness), just re-set the current backlight level, which also takes
care of enabling the backlight if necessary.

Only the radeon_atom_encoder_dpms_dig part tested on a Kaveri laptop,
the radeon_atom_encoder_dpms_avivo part is only compile tested.

Cc: stable@vger.kernel.org
Signed-off-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

The "i" variable should be signed or it leads to a crash in the error
handling code.

Fixes: 1d263474 ('drm/amdgpu: unwind properly in amdgpu_cs_parser_init()')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

A previous commit resets the Context Status Buffer (CSB) read pointer in
ring init
    commit c0a03a2e ("drm/i915: Reset CSB read pointer in ring init")

This is generally correct, but this pointer is not reset after
suspend/resume in some platforms (cht). In this case, the driver should
read the register value instead of resetting the sw read counter to 0.
Otherwise we process old events, leading to unwanted pre-emptions or
something worse.

But in other platforms (bdw) and also during GPU reset or power up, the
CSBWP is reset to 0x7 (an invalid number), and in this case the read
pointer should be set to 5 (the interrupt code will increment this
counter one more time, and will start reading from CSB[0]).

v2: When the CSB registers are reset, the read pointer needs to be set
to 5, otherwise the first write (CSB[0]) won't be read (Mika).
Replace magic numbers with GEN8_CSB_ENTRIES (6) and GEN8_CSB_PTR_MASK
(0x07).

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: NLei Shen <lei.shen@intel.com>
Signed-off-by: NDeepak S <deepak.s@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

In case something goes wrong with power well initialization we were calling
intel_prepare_ddi during boot while encoder list isnt't initilized.

[    9.618747] i915 0000:00:02.0: Invalid ROM contents
[    9.631446] [drm] failed to find VBIOS tables
[    9.720036] BUG: unable to handle kernel NULL pointer dereference at 00000000
00000058
[    9.721986] IP: [<ffffffffa014eb72>] ddi_get_encoder_port+0x82/0x190 [i915]
[    9.723736] PGD 0
[    9.724286] Oops: 0000 [#1] PREEMPT SMP
[    9.725386] Modules linked in: intel_powerclamp snd_hda_intel(+) coretemp crc
32c_intel snd_hda_codec snd_hda_core serio_raw snd_pcm snd_timer i915(+) parport
_pc parport pinctrl_sunrisepoint pinctrl_intel nfsd nfs_acl
[    9.730635] CPU: 0 PID: 497 Comm: systemd-udevd Not tainted 4.3.0-rc2-eywa-10
967-g72de2cfd-dirty #2
[    9.732785] Hardware name: Intel Corporation Cannonlake Client platform/Skyla
ke DT DDR4 RVP8, BIOS CNLSE2R1.R00.X021.B00.1508040310 08/04/2015
[    9.735785] task: ffff88008a704700 ti: ffff88016a1ac000 task.ti: ffff88016a1a
c000
[    9.737584] RIP: 0010:[<ffffffffa014eb72>]  [<ffffffffa014eb72>] ddi_get_enco
der_port+0x82/0x190 [i915]
[    9.739934] RSP: 0000:ffff88016a1af710  EFLAGS: 00010296
[    9.741184] RAX: 000000000000004e RBX: ffff88008a9edc98 RCX: 0000000000000001
[    9.742934] RDX: 000000000000004e RSI: ffffffff81fc1e82 RDI: 00000000ffffffff
[    9.744634] RBP: ffff88016a1af730 R08: 0000000000000000 R09: 0000000000000578
[    9.746333] R10: 0000000000001065 R11: 0000000000000578 R12: fffffffffffffff8
[    9.748033] R13: ffff88016a1af7a8 R14: ffff88016a1af794 R15: 0000000000000000
[    9.749733] FS:  00007eff2e1e07c0(0000) GS:ffff88016fc00000(0000) knlGS:00000
00000000000
[    9.751683] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    9.753083] CR2: 0000000000000058 CR3: 000000016922b000 CR4: 00000000003406f0
[    9.754782] Stack:
[    9.755332]  ffff88008a9edc98 ffff88008a9ed800 ffffffffa01d07b0 00000000fffb9
09e
[    9.757232]  ffff88016a1af7d8 ffffffffa0154ea7 0000000000000246 ffff88016a370
080
[    9.759182]  ffff88016a370080 ffff88008a9ed800 0000000000000246 ffff88008a9ed
c98
[    9.761132] Call Trace:
[    9.761782]  [<ffffffffa0154ea7>] intel_prepare_ddi+0x67/0x860 [i915]
[    9.763332]  [<ffffffff81a56996>] ? _raw_spin_unlock_irqrestore+0x26/0x40
[    9.765031]  [<ffffffffa00fad01>] ? gen9_read32+0x141/0x360 [i915]
[    9.766531]  [<ffffffffa00b43e1>] skl_set_power_well+0x431/0xa80 [i915]
[    9.768181]  [<ffffffffa00b4a63>] skl_power_well_enable+0x13/0x20 [i915]
[    9.769781]  [<ffffffffa00b2188>] intel_power_well_enable+0x28/0x50 [i915]
[    9.771481]  [<ffffffffa00b4d52>] intel_display_power_get+0x92/0xc0 [i915]
[    9.773180]  [<ffffffffa00b4fcb>] intel_display_set_init_power+0x3b/0x40 [i91
5]
[    9.774980]  [<ffffffffa00b5170>] intel_power_domains_init_hw+0x120/0x520 [i9
15]
[    9.776780]  [<ffffffffa0194c61>] i915_driver_load+0xb21/0xf40 [i915]

So let's protect this case.

My first attempt was to remove the intel_prepare_ddi, but Daniel had pointed out
this is really needed to restore those registers values. And Imre pointed out
that this case was without the flag protection and this was actually where things
were going bad. So I've just checked and this indeed solves my issue.

The regressing intel_prepare_ddi call was added in

commit 1d2b9526
Author: Damien Lespiau <damien.lespiau@intel.com>
Date:   Fri Mar 6 18:50:53 2015 +0000

    drm/i915/skl: Restore the DDI translation tables when enabling PW1

Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
[Jani: regression reference]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>