Kernel and userspace are able to handle 4GB (1<<32) address space range,
but "A32 Stateless Model" is not. According to documentation, A32 accesses
are based on General State Base Address and bound checking is in place.
Because size field (instruction State Base Address) limitation, it is not
possible to address full 4GB memory region.

A32 Stateless Model is used by some libraries and without this patch, the
last page of 4GB address space is not accessible in 32bit processes.
Reported-by: NArtur Harasimiuk <artur.harasimiuk@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452512367-23614-1-git-send-email-michel.thierry@intel.com
Cc: drm-intel-fixes@lists.freedesktop.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

sanitize_watermarks() does not properly handle errors returned by
drm_atomic_helper_duplicate_state().  Make failures drop locks before
returning.  We also change the lock of connection_mutex to a
drm_modeset_lock_all_ctx() to make sure any EDEADLK's are handled
earlier.

v2: Change call to lock connetion_mutex with a call to
    drm_modeset_lock_all_ctx().  This ensures that any lock contention
    is handled earlier and drm_atomic_helper_duplicate_state() won't
    return EDEADLK. (Maarten)

v3: Drop locks properly in more error paths. (Maarten)

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452611617-32144-1-git-send-email-matthew.d.roper@intel.com

commit 10afa0b6 ("drm/i915: Reject >9 ddi translation entried if port != A/E on SKL")
added sanity checks to make sure we don't end up with too many ddi translation
values for eDP ports, but it actually failed to check if the port is eDP.
We still look up the edp translations for non-eDP ports, but don't use
them, so we shouldn't be complaining about them either.

Fixes: 10afa0b6 ("drm/i915: Reject >9 ddi translation entried if port != A/E on SKL")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452612496-9201-1-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

MI_BATCH_BUFFER is nasty since it requires that userspace pass in the
correct batch length.

Let's switch to using MI_BATCH_BUFFER_START instead (like we do on
other platforms). Then we don't have to specify the batch length
at all, and the CS will instead execute until it sees the
MI_BATCH_BUFFER_END.

We still need the batch length since we do the CS TLB workaround
and copy the batch into the permanently pinned scratch object
and execute it from there. But for this we can simply use the
batch object length when the user hasn't specified the actual
batch length. So specifying the batch length becomes just a
way to optimize the batch copy a little bit.

We lost batch_len from a bunch of igts (including the quiesce batch)
so without this igt is utterly broken on 830/845. Also some igts such
as gem_cpu_reloc never specified the batch_len and so didn't work.
With MI_BATCH_BUFFER_START we don't have to fix up igt every time
someone forgets that 830/845 exist.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450110229-30450-11-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

My 830 has VBT version 105 with child device size of 22 bytes.
Let's assume that's correct and adjust our expectations.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450110229-30450-9-git-send-email-ville.syrjala@linux.intel.comAcked-by: NJani Nikula <jani.nikula@intel.com>

My 85x has VBT version 108 which has a child dev size of 27 bytes.
Let's allow that without printing an error.

We still want to reject the actual parsin since for that we need
the child device size to be at least 33 bytes. So we should still
check for that, but let's make it print a debug message only instead
of an error.

While at it, toss in a BUILD_BUG_ON() to verify our struct
old_child_dev_config is in fact 33 bytes.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450110229-30450-8-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

We use the vblank timestamps to generate the vblank frame counter value
on gen2. That means we need the pipe scanout position to be accurate
when we call drm_crtc_vblank_on(), otherwise the frame counter
guesstimate may jump when the pipe actually start.

What I observed on my 85x is that the DSL initially reads 0, and when
the pipe actually starts DSL jumps to vblank_start. On gen2 DSL==0 means
actually vtotal-1 (see update_scanline_offset()), so if we initially
get vtotal-1, and then very quickly vblank_start (or thereabouts), the
scanout position will appear to jump backwards by approximately one
vblank length. Which means the frame counter guesstimate will also
jump backwards. That's no good, so let's make sure the pipe has
started before we call drm_crtc_vblank_on().
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450110229-30450-5-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Restore the lost phys status page cleanup.

Fixes the following splat with DMA_API_DEBUG=y:

WARNING: CPU: 0 PID: 21615 at ../lib/dma-debug.c:974 dma_debug_device_change+0x190/0x1f0()
pci 0000:00:02.0: DMA-API: device driver has pending DMA allocations while released from device [count=1]
               One of leaked entries details: [device address=0x0000000023163000] [size=4096 bytes] [mapped with DMA_BIDIRECTIONAL] [mapped as coherent]
Modules linked in: i915(-) i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm sha256_generic hmac drbg ctr ccm sch_fq_codel binfmt_misc joydev mousedev arc4 ath5k iTCO_wdt mac80211 smsc_ircc2 ath snd_intel8x0m snd_intel8x0 snd_ac97_codec ac97_bus psmouse snd_pcm input_leds i2c_i801 pcspkr snd_timer cfg80211 snd soundcore i2c_core ehci_pci firewire_ohci ehci_hcd firewire_core lpc_ich 8139too rfkill crc_itu_t mfd_core mii usbcore rng_core intel_agp intel_gtt usb_common agpgart irda crc_ccitt fujitsu_laptop led_class parport_pc video parport evdev backlight
CPU: 0 PID: 21615 Comm: rmmod Tainted: G     U          4.4.0-rc4-mgm-ovl+ #4
Hardware name: FUJITSU SIEMENS LIFEBOOK S6120/FJNB16C, BIOS Version 1.26  05/10/2004
 e31a3de0 e31a3de0 e31a3d9c c128d4bd e31a3dd0 c1045a0c c15e00c4 e31a3dfc
 0000546f c15dfad2 000003ce c12b3740 000003ce c12b3740 00000000 00000001
 f61fb8a0 e31a3de8 c1045a83 00000009 e31a3de0 c15e00c4 e31a3dfc e31a3e4c
Call Trace:
 [<c128d4bd>] dump_stack+0x16/0x19
 [<c1045a0c>] warn_slowpath_common+0x8c/0xd0
 [<c12b3740>] ? dma_debug_device_change+0x190/0x1f0
 [<c12b3740>] ? dma_debug_device_change+0x190/0x1f0
 [<c1045a83>] warn_slowpath_fmt+0x33/0x40
 [<c12b3740>] dma_debug_device_change+0x190/0x1f0
 [<c1065499>] notifier_call_chain+0x59/0x70
 [<c10655af>] __blocking_notifier_call_chain+0x3f/0x80
 [<c106560f>] blocking_notifier_call_chain+0x1f/0x30
 [<c134cfb3>] __device_release_driver+0xc3/0xf0
 [<c134d0d7>] driver_detach+0x97/0xa0
 [<c134c440>] bus_remove_driver+0x40/0x90
 [<c134db18>] driver_unregister+0x28/0x60
 [<c1079e8c>] ? trace_hardirqs_on_caller+0x12c/0x1d0
 [<c12c0618>] pci_unregister_driver+0x18/0x80
 [<f83e96e7>] drm_pci_exit+0x87/0xb0 [drm]
 [<f8b3be2d>] i915_exit+0x1b/0x1ee [i915]
 [<c10b999c>] SyS_delete_module+0x14c/0x210
 [<c1079e8c>] ? trace_hardirqs_on_caller+0x12c/0x1d0
 [<c115a9bd>] ? ____fput+0xd/0x10
 [<c1002014>] do_fast_syscall_32+0xa4/0x450
 [<c149f6fa>] sysenter_past_esp+0x3b/0x5d
---[ end trace c2ecbc77760f10a0 ]---
Mapped at:
 [<c12b3183>] debug_dma_alloc_coherent+0x33/0x90
 [<f83e989c>] drm_pci_alloc+0x18c/0x1e0 [drm]
 [<f8acd59f>] intel_init_ring_buffer+0x2af/0x490 [i915]
 [<f8acd8b0>] intel_init_render_ring_buffer+0x130/0x750 [i915]
 [<f8aaea4e>] i915_gem_init_rings+0x1e/0x110 [i915]

v2: s/BUG_ON/WARN_ON/ since dim doens't like the former anymore

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: 5c6c6003 ("drm/i915: Remove DRI1 ring accessors and API")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Link: http://patchwork.freedesktop.org/patch/msgid/1452538112-5331-1-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Move the ddi buffer translation programming to occur from the encoder
.pre_enable() hook, for just the ddi port we are enabling. Previously
we used to reprogram the translations for all ddi ports during
init and during power well enabling.

v2: s/intel_prepare_ddi_buffers/intel_prepare_ddi_buffer/ (Daniel)
    Resolve conflicts due to  dev_priv->atomic_cdclk_freq
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Only DDI A and E support 10 translation entries in DP mode. For the
other ports the tenth entry is reserved for HDMI.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449597590-6971-9-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Make the ddi buffer programming code a bit more neat by passing
around dev_priv instead of dev.

v2: Resolve conflicts due to KBL
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v1)

skl_get_buf_trans_edp() effectively contains another copy of
skl_get_buf_trans_dp(). Remove the duplication and just call
skl_get_buf_trans_dp() from  skl_get_buf_trans_edp().

v2: Resolve conflicts due to KBL
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v1)

skl_get_buf_trans_*() don't need the 'ddi_translations' local variable
since all they with is assign and return. Just return the right thing
directly and get rid of the local variable.

v2: Resolve conflicts due to KBL
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v1)

Rather than having open coded checks for the DDI A/E configuration,
just store the max supported lane count in intel_digital_port.

We had an open coded check for DDI A, but not for DDI E. So we may
have been vilating the DDI E max lane count.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

DDI A and E share some of the lanes, so check that we have enough
lanes for the purpose we need before registering the encoders.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449597590-6971-3-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We're supposed to pass the primary DP encoder to intel_ddi_clk_select(),
not the fake MST encoder. Do so.

There's no real bug here though, since intel_ddi_clk_select() only
checks if the encoder type is EDP (which it isn't for either the
primary DP encoder or the fake MST encoder), and it gets the DDI port
via intel_ddi_get_encoder_port() (which knows how to do the
fake->primary->port dance itself).

Fixes: e404ba8d ("drm/i915: Setup DDI clk for MST on SKL")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449597590-6971-2-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Same effect for slightly less source code and resulting binary.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1452521321-4032-2-git-send-email-tvrtko.ursulin@linux.intel.com

Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452006497-28517-1-git-send-email-jani.nikula@intel.com

Make it a bit tidier and safer.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/cab24a84811ddbae72d8c3a5f59d29f57b1d3aad.1450702954.git.jani.nikula@intel.com

The sequence block has sizes of elements after the operation byte since
sequence block v3. Use it to skip elements we don't support yet.

v2: remove redundant exec_elem[operation_byte] check (Daniel)
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452006408-27688-1-git-send-email-jani.nikula@intel.com

The changes since the sequence block v2 are:

* The whole MIPI bios data block has a separate 32-bit size field since
  v3, stored after the version. This facilitates big sequences.

* The size of the panel specific sequence blocks has grown to 32
  bits. This facilitates big sequences.

* The elements within sequences now have an 8-bit size field following
  the operation byte. This facilitates skipping unknown new operation
  bytes, i.e. forward compatibility.

v2 (of the patch): use DRM_ERROR for unknown operation byte
v3 (of the patch): even more bounds checking (Ville)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452518102-3154-1-git-send-email-jani.nikula@intel.com

New sequences, new operations within sequences.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/96335b9fb875f79882d694360bff060251bd2f17.1450702954.git.jani.nikula@intel.com

Don't choke on unknown elements when we do know how to skip them.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452518948-16469-1-git-send-email-jani.nikula@intel.com

Properly parse the new sequences added in MIPI sequence block v2.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/cc1551bdfc4392d02413b78179f3a65c786c75ab.1450702954.git.jani.nikula@intel.com

Add parsing of the i2c element, defined in MIPI sequence block v2. Drop
the status operation byte while at it, that does not exist.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/d8a2998977feee2f5b5ad609aaca787adfb41479.1450702954.git.jani.nikula@intel.com

If we go into suspend with unclaimed access detected,
it would be nice to catch that access on a next suspend path.
So instead of just notifying about it, arm the unclaimed
mmio checks on suspend side.

We want to keep the asymmetry on resume, as if it was
on resume path, it was not driver that is responsible so
no point in arming mmio debugs.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1452261080-6979-2-git-send-email-mika.kuoppala@intel.com

With commit 8ac3e1bb ("drm/i915: Add non claimed mmio checking
for vlv/chv") we now have chv/vlv support in place for detecting
unclaimed access. Also the perf hit of extra mmio read
is now only suffered if mmio_debug is set.

This allows us to stuff the macro for unclaimed reg
detection inside a generic gen6 register access, as now all
gens using these macros uses also unclaimed debugs, the one
exception being snb. We gain more clean and generic macros
and only downside is that snb will suffer one branch perf hit
without upside.

Note that the hsw write path debug register check now
happens before fifo check, but this should not make
any real difference.

As vlv/chv use the generic gen6 access macros, the consequence
is that they gain the mmio_debug feature.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1452261080-6979-1-git-send-email-mika.kuoppala@intel.com

This fixes a spurious warning from an integer overflow on 64-bits systems.
The function may return MAX_SCHEDULE_TIMEOUT which gets truncated to -1.

Explicitly handling this by casting to lret fixes it.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-and-tested-by: NJoseph Yasi <joe.yasi@gmail.com>
Tested-by: NAndreas Reis <andreas.reis@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: drm-intel-fixes@lists.freedesktop.org
Fixes: 3c28ff22 ("i915: wait for fence in prepare_plane_fb")
Link: http://patchwork.freedesktop.org/patch/msgid/5666EEC8.2000403@linux.intel.com

Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Extend the same reasoning as in the patch listed below.  It's not an
error for the workaround list to be empty if no workarounds are needed.

    commit 02235808
    Author: Francisco Jerez <currojerez@riseup.net>
    Date:   Wed Oct 7 14:44:01 2015 +0300
        drm/i915: Don't warn if the workaround list is empty.
Signed-off-by: NWayne Boyer <wayne.boyer@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452129330-3484-2-git-send-email-rodrigo.vivi@intel.com

When adding IS_KABYLAKE definition I didn't included the
DC states related because I was planing to include them
with the patch that fixes DMC firmware loading, but I
forgot them.

Meanwhile this runtime pm code changed a lot for
Skylake.

Well, I didn't expect that this would crash the machine
and I just noticed now that Sarah warned me our driver
wasn't working. Thanks Sarah.

Michel had found the main error first and his
fix had better details on the history and got
merged already:

commit 16fbc291
Author: Michel Thierry <michel.thierry@intel.com>
Date:   Wed Jan 6 12:08:36 2016 +0000

    drm/i915/kbl: Enable PW1 and Misc I/O power wells

This one is a follow-up adding the other remaining
missing pieces.

v2: Rebased on top of Michel's patch as explained above.

Cc: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452214179-22361-1-git-send-email-rodrigo.vivi@intel.com

The dsi_rr_formula() function has been unused for almost two years,
since

commit 44d4c6ee
Author: Shobhit Kumar <shobhit.kumar@intel.com>
Date:   Tue Dec 10 12:14:56 2013 +0530

    drm/i915: Compute dsi_clk from pixel clock

citing the reason as pixel clock based calculation being recommended in
the MIPI host controller documentation. Remove the dead code, we can
always bring it back if it's needed.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452249940-2605-2-git-send-email-jani.nikula@intel.com

Hide away the platform differences in intel_dsi_get_pckl() within
intel_dsi_pll.c. No functional changes.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452249940-2605-1-git-send-email-jani.nikula@intel.com

Imre mentioned that chv might also have capability to
track unclaimed mmio accesses. Ville added that
both chv and vlv has this capability and he had already
made this way back [1]. Mimic what Ville's patch does
but adapt on top of less frequent mmio accesses by
omitting checking always on reg writes.

This patch is untested as of now.

v2: overflow handling and posting omitted (Ville)

References: [1] http://lists.freedesktop.org/archives/intel-gfx/2013-May/027599.html
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450201542-22918-1-git-send-email-mika.kuoppala@intel.com

Remove char* assignments and add branching hint and
also constify the parameters.

This results in a 35 bytes shorter fast path, so author
boldly assumes it helps without doing in-depth assembly
analysis.

v2: use WARN's branching (Chris), commit name (Joonas)

Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450189512-30360-5-git-send-email-mika.kuoppala@intel.com

We have done unclaimed register access check in normal
(mmio_debug=0) mode once per write. This adds probability
of finding the exact sequence where we did the bad access, but
also adds burden to each write.

As we have mmio_debug available for more fine grained analysis,
give up accuracy of detecting correct spot at the first occurrence
by doing the one shot detection and arming of mmio_debug in hangcheck
and in modeset. This removes the write path performance burden.

v2: Remove gratuitous DRM_DEBUG and return value, comments (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450250808-14864-1-git-send-email-mika.kuoppala@intel.com

If something, the usual suspect being bios, access hw
behind our back, don't let it slide into situation where
normal register access will detect this and spit out
a warn on into dmesg. On some bdw bioses this happens
during igt/bat run always and as there is not much we can
do about it, its better just to detect and flush this
explicitly on resume and only print a debug message.

v2: use DRM_DEBUG_DRIVER (Chris)
v3: s/access/mmio, s/prior/prior to, s/dev/dev_priv

Testcase: igt/pm_rpm/basic-rte
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
[Mika: fixed merge conflict]
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450189512-30360-3-git-send-email-mika.kuoppala@intel.com

Currently interrupt code is the only place checking
for the unclaimed register access prior to actual register
macros using the same functionality. Rename the function
and make it return bool so that the possible error message
context is clear in the caller side. The motivation is to allow
usage of unclaimed detection on arbitrary places.

v2: rebase, s/access/mmio, s/dev/dev_priv
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450189512-30360-2-git-send-email-mika.kuoppala@intel.com

Access the unclaimed reg detection register through
one helper which also does cleanup. Note that we now access
the register only if the platform has the actual non claimed
access bit. This prevents reading the register with gens that
doesn't have the register or the unclaimed bit,
when debug_mmio > 0.

Note that we post after clearing the bit. This makes sure
that the next unclaimed write access would get detected
also if it happened right after clearing, and not fold
into the previous detection.

v2: s/unclaimed_reg_access/check_for_unclaimed_mmio (Chris)
    debug log on unclaimed detection on uncore init (Joonas)

v3: remove posting read (Ville)

Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450200287-24080-1-git-send-email-mika.kuoppala@intel.com

If head seems stuck and engine in question is rcs,
inspect subunit state transitions from undone to done,
before deciding that this really is a hang instead of limited
progress. Only account the transitions of subunits from
undone to done once, to prevent unstable subunit states
to keep us falsely active.

As this adds one extra steps to hangcheck heuristics,
before hang is declared, it adds 1500ms to to detect hang
for render ring to a total of 7500ms. We could sample
the subunit states on first head stuck condition but
decide not to do so only in order to mimic old behaviour. This
way the check order of promotion from seqno > atchd > instdone
is consistently done.

v2: Deal with unstable done states (Arun)
    Clear instdone progress on head and seqno movement (Chris)
    Report raw and accumulated instdone's in in debugfs (Chris)
    Return HANGCHECK_ACTIVE on undone->done

References: https://bugs.freedesktop.org/show_bug.cgi?id=93029
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448985372-19535-1-git-send-email-mika.kuoppala@intel.com