Rename pipe_config_err() to pipe_config_mismatch(), and also print
whether we're doing the fastset check or the sw vs. hw state readout
check. Should make the logs a bit less confusing when they're not
filled with what looks like a real error.

Also rename the 'adjust' variable to 'fastset' to make it clear what
it means.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612130801.2085-3-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

Now that intel_pipe_config_compare() no longer clobbers the passed
in state we can make both crtc states const. And while at we simplify
the calling convention, and clean up intel_compare_link_m_n() a bit.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612130801.2085-2-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

We're now calling intel_pipe_config_compare(..., true) uncoditionally
which means we're always going clobber the calculated M/N values with
the old values if the fuzzy M/N check passes. That causes problems
because the fuzzy check allows for a huge difference in the values.

I'm actually tempted to just make the M/N checks exact, but that might
prevent fastboot from kicking in when people want it. So for now let's
overwrite the computed values with the old values only if decide to skip
the modeset.

v2: Copy has_drrs along with M/N M2/N2 values

Cc: stable@vger.kernel.org
Cc: Blubberbub@protonmail.com
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Tested-by: Blubberbub@protonmail.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110782
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110675
Fixes: d19f958d ("drm/i915: Enable fastset for non-boot modesets.")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612172423.25231-1-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

Since commit 1ba62714 ("drm: Add reservation_object to
drm_gem_object"), struct drm_gem_object grew its own builtin
reservation_object rendering our own private one bloat. Remove our
redundant reservation_object and point into obj->base.resv instead.

References: 1ba62714 ("drm: Add reservation_object to drm_gem_object")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618125858.7295-1-chris@chris-wilson.co.uk

Though we pin the context first before taking the pm wakeref, during
retire we need to unpin before dropping the pm wakeref (breaking the
"natural" onion). During the unpin, we may need to attach a cleanup
operation on to the engine wakeref, ergo we want to keep the engine
awake until after the unpin.

v2: Push the engine wakeref into the barrier so we keep the onion unwind
ordering in the request itself

Fixes: ce476c80 ("drm/i915: Keep contexts pinned until after the next kernel context switch")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618074153.16055-1-chris@chris-wilson.co.uk

If the user is clearing the log buffer too slowly, we overflow. As this
is an expected condition, and the driver tries to handle it, reduce the
error message down to a notice.

Michal mentioned that another cause would be incorrect reset handling,
so we don't want to lose the notification entirely.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110817Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190617100917.13110-1-chris@chris-wilson.co.uk

Fix the plethora of Sphinx build errors after moving the display files
under a subdirectory.

Fixes: 379bc100 ("drm/i915: move modesetting output/encoder code under display/")
Fixes: df0566a6 ("drm/i915: move modesetting core code under display/")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190617102944.25129-1-jani.nikula@intel.com

Although EHL introduces a new PCH, the South Display part of the PCH
that we care about is nearly identical to ICP, just with some pins
remapped.  Most notably, Port C is mapped to the pins that ICP uses for
TC Port 1.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190615004210.16656-1-matthew.d.roper@intel.com

Currently, we perform a locked update of the shadow entry when
allocating a page directory entry such that if two clients are
concurrently allocating neighbouring ranges we only insert one new entry
for the pair of them. However, we also need to serialise both clients
wrt to the actual entry in the HW table, or else we may allow one client
or even a third client to proceed ahead of the HW write. My handwave
before was that under the _pathological_ condition we would see the
scratch entry instead of the expected entry, causing a temporary
glitch. That starvation condition will eventually show up in practice, so
fix it.

The reason for the previous cheat was to avoid having to free the extra
allocation while under the spinlock. Now, we keep the extra entry
allocated until the end instead.

v2: Fix error paths for gen6

Fixes: 1d1b5490 ("drm/i915/gtt: Replace struct_mutex serialisation for allocation")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190617140426.7203-1-chris@chris-wilson.co.uk

In intel_package_header version 2 there's a new field in the
fw_info table that must be 0, otherwise it's not the correct DMC
firmware. Add a check for version 2 or later.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-10-lucas.demarchi@intel.com

parse_csr_fw() is responsible to set up several fields in struct intel_csr,
including the payload. We don't need to assign it again.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-9-lucas.demarchi@intel.com

Main difference is that now there are up to 20 MMIOs that can be set and
a lot of noise due to the struct changing the fields in the middle.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-8-lucas.demarchi@intel.com

Complete the extraction of functions to parse specific parts of the
firmware. The return of the function parse_csr_fw() is now redundant
since it already sets the dmc_payload field. Changing it is left for
later to avoid noise in the commit.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-7-lucas.demarchi@intel.com

Like parse_csr_fw_css() this parses the package_header from firmware and
saves the relevant fields in the csr struct. In this function we also
lookup the fw_info we are interested in.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-6-lucas.demarchi@intel.com

Let's start splitting the parse function, making all of them return the
number of bytes parsed - different versions of the firmware header may
require different sizes for the structures.

v2: rework remaining bytes calculation on new protection for amount of
    bytes read
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-5-lucas.demarchi@intel.com

The only meaninful change is that it supports up to 32 fw_info entries
rather than the previous max=20.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-4-lucas.demarchi@intel.com

Move fw_info out of struct intel_package_header to allow it to grow more
easily in future. To make a cleaner move, let's also extract a function to
search the header for the dmc_offset.

While reviewing this code I wondered why we continued the search even
after finding a suitable firmware. Add a comment to explain we will
continue to try to find a more specific firmware version, even if this
is not required by the spec.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-3-lucas.demarchi@intel.com

Change all fields in intel_package_header and intel_dmc_header whose
meaning are 1-byte numbers to use u8.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-2-lucas.demarchi@intel.com

Allocate all page directory variants with alloc_pd. As
the lvl3 and lvl4 variants differ in manipulation, we
need to check for existence of backing phys page before accessing
it.

v2: use err in returns
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-5-mika.kuoppala@linux.intel.com

All page directories, excluding last level, are initialized with
pointer to next level page directories. Make common function for it.
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-4-mika.kuoppala@linux.intel.com

We set the page directory entries to point into a page table.
There is no gen specifics in here so make it simple and
obvious.
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-3-mika.kuoppala@linux.intel.com

All page directories are identical in function, only the position in the
hierarchy differ. Use same base type for directory functionality.

v2: cleanup, size always 512, init to null

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-2-mika.kuoppala@linux.intel.com

We set them to scratch right after allocation so prevent
useless zeroing before.

v2: atomic_t
v3: allow pdp alloc fail

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-1-mika.kuoppala@linux.intel.com

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613145229.21389-1-jani.nikula@intel.com

Now that we have a new subdirectory for display code, continue by moving
modesetting core code.

display/intel_frontbuffer.h sticks out like a sore thumb, otherwise this
is, again, a surprisingly clean operation.

v2:
- don't move intel_sideband.[ch] (Ville)
- use tabs for Makefile file lists and sort them

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613084416.6794-3-jani.nikula@intel.com

ICL introduces a new gamma correction mode in display engine, called
multi-segmented-gamma mode. This mode allows users to program the
darker region of the gamma curve with sueprfine precision. An
example use case for this is HDR curves (like PQ ST-2084).

If we plot a gamma correction curve from value range between 0.0 to 1.0,
ICL's multi-segment has 3 different sections:
- superfine segment: 9 values, ranges between 0 - 1/(128 * 256)
- fine segment: 257 values, ranges between 0 - 1/(128)
- corase segment: 257 values, ranges between 0 - 1

This patch:
- Changes gamma LUTs size for ICL/GEN11 to 262144 entries (8 * 128 * 256),
  so that userspace can program with highest precision supported.
- Changes default gamma mode (non-legacy) to multi-segmented-gamma mode.
- Adds functions to program/detect multi-segment gamma.

V2: Addressed review comments from Ville
    - separate function for superfine and fine segments.
    - remove enum for segments.
    - reuse last entry of the LUT as gc_max value.
    - replace if() ....cond with switch...case in icl_load_luts.
    - add an entry variable, instead of 'word'

V3: Addressed review comments from Ville
    - extra newline
    - s/entry/color/
    - remove LUT size checks
    - program ilk_lut_12p4_ldw value before ilk_lut_12p4_udw
    - Change the comments in description of fine and coarse segments,
      and try to make more sense.
    - use 8 * 128 instead of 1024
    - add 1 entry in LUT for GCMAX

V4: Addressed review comments from Ville
    - Remove unused macro
    - missing shift entry in blue
    - pick correct entry for GCMAX
    - Added Ville's R-B
Note: Tested and confirmed the programming sequence of odd/even
registers in the HW. The correct sequence should be:
	ilk_lut_12p4_udw
	ilk_lut_12p4_ldw

v5: Addressed Ville's review comments and renamed odd/even register
helpers to be more consistent with the values.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Signed-off-by: NUma Shankar <uma.shankar@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-5-git-send-email-uma.shankar@intel.com

This patch renames function ivb_load_lut_10_max to
ivb_load_lut_ext_max.

V3: Added Vill'es r-b.

Cc: Uma Shankar <uma.shankar@intel.com>
Suggested-by: NVille Syrjala <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-4-git-send-email-uma.shankar@intel.com

Add macros to define multi segmented gamma registers

V2: Addressed Ville's comments:
    	Add gen-lable before bit definition
    Addressed Jani's comment
	- Use REG_GENMASK() and REG_BIT()
V3: Addressed Ville's comments:
    - Put comments at the end of line.
    - Change the comment at start of ICL multisegmented gamma registers.
    Added Ville's r-b

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NUma Shankar <uma.shankar@intel.com>
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-3-git-send-email-uma.shankar@intel.com

Currently, data type of gamma_lut_size & degamma_lut_size elements
in intel_device_info is u16, which means it can accommodate maximum
64k values. In case of ICL multisegmented gamma, the size of gamma
LUT is 256K.

This patch changes the data type of both of these elements to u32.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>

V4: Added Uma's r-b.
Reviewed-by: NUma Shankar <uma.shankar@intel.com>
Signed-off-by: NShashank Sharma <shashank.sharma@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-2-git-send-email-uma.shankar@intel.com

They have been unused since rotation was added to drm core in 2015,
time to get rid of them.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611132820.31981-1-maarten.lankhorst@linux.intel.comReviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Add a new subdirectory for display code, and start off by moving
modesetting output/encoder code. Judging by the include changes, this is
a surprisingly clean operation.

v2:
- move intel_sdvo_regs.h too
- use tabs for Makefile	file lists and sort them

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613084416.6794-2-jani.nikula@intel.com

Ensure intel_sdvo_regs.h is self-contained and remains that way.

v2:
- include <linux/compiler.h> for __packed (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613100818.24800-1-jani.nikula@intel.com

EHL defines two new MOCS table entries but is otherwise compatible with
the ICL MOCS table.

These table entries (16 and 17) should still be considered unused for
ICL and as such their behavior remains undefined for that platform.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190530234014.22340-1-matthew.d.roper@intel.comReviewed-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>

While we need to flush the wakeref before parking, we do not need to
perform the i915_gem_park() itself underneath the wakeref lock, merely
the struct_mutex. If we rearrange the locks, we can avoid the unnecessary
tainting.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614220616.24932-1-chris@chris-wilson.co.uk

To continue the onslaught of removing the assumption of a global
execution ordering, another casualty is the engine->timeline. Without an
actual timeline to track, it is overkill and we can replace it with a
much less grand plain list. We still need a list of requests inflight,
for the simple purpose of finding inflight requests (for retiring,
resetting, preemption etc).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-3-chris@chris-wilson.co.uk

We no longer track the execution order along the engine and so no longer
need to enforce ordering of retire along the engine.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-2-chris@chris-wilson.co.uk

We need to keep the context image pinned in memory until after the GPU
has finished writing into it. Since it continues to write as we signal
the final breadcrumb, we need to keep it pinned until the request after
it is complete. Currently we know the order in which requests execute on
each engine, and so to remove that presumption we need to identify a
request/context-switch we know must occur after our completion. Any
request queued after the signal must imply a context switch, for
simplicity we use a fresh request from the kernel context.

The sequence of operations for keeping the context pinned until saved is:

 - On context activation, we preallocate a node for each physical engine
   the context may operate on. This is to avoid allocations during
   unpinning, which may be from inside FS_RECLAIM context (aka the
   shrinker)

 - On context deactivation on retirement of the last active request (which
   is before we know the context has been saved), we add the
   preallocated node onto a barrier list on each engine

 - On engine idling, we emit a switch to kernel context. When this
   switch completes, we know that all previous contexts must have been
   saved, and so on retiring this request we can finally unpin all the
   contexts that were marked as deactivated prior to the switch.

We can enhance this in future by flushing all the idle contexts on a
regular heartbeat pulse of a switch to kernel context, which will also
be used to check for hung engines.

v2: intel_context_active_acquire/_release
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-1-chris@chris-wilson.co.uk

intel_runtime_pm is the only thing they use from the i915 structure,
so use that directly.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613232156.34940-9-daniele.ceraolospurio@intel.com

Matching the underlying get/put functions.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613232156.34940-8-daniele.ceraolospurio@intel.com

The functions where internally already only using the structure, so we
need to just flip the interface.

v2: rebase
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613232156.34940-7-daniele.ceraolospurio@intel.com