Just like single link MIPI panels, similarly for dual link panels, pipe
to be configured is based on the DVO port from VBT Block 2. In hardware,
Port A is mapped with Pipe A and Port C is mapped with Pipe B.

This issue got introduced in -

commit 7e9804fd
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Fri Jan 16 14:27:23 2015 +0200

    drm/i915/dsi: add drm mipi dsi host support

Cc: stable@vger.kernel.org # v4.0
Signed-off-by: NGaurav K Singh <gaurav.k.singh@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If one disables DDR DVFS in the BIOS, Punit will apparently ignores
all DDR DVFS request. Currently we assume that DDR DVFS is always
operational, which leads to errors in dmesg when the DDR DVFS requests
time out.

Fix the problem by gently prodding Punit during driver load to find out
whether it will respond to DDR DVFS requests. If the request times out,
we assume that DDR DVFS has been permanenly disabled in the BIOS and
no longer perster the Punit about it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91629Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NClint Taylor <Clinton.A.Taylor@intel.com>
Tested-by: NClint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Fix a wrong logical AND (&&) used for the range check of CSR MMIO.

Spotted nicely by gcc -Wlogical-op flag:
  drivers/gpu/drm/i915/intel_csr.c: In function ‘finish_csr_load’:
  drivers/gpu/drm/i915/intel_csr.c:353:41: warning: logical ‘and’ of mutually exclusive tests is always false [-Wlogical-op]

Fixes: eb805623 ('drm/i915/skl: Add support to load SKL CSR firmware.')
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NAnimesh Manna <animesh.manna@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

In I915_READ64_2x32 we attempt to read a 64bit register using 2 32bit
reads. Due to the nature of the registers we try to read in this manner,
they may increment between the two instruction (e.g. a timestamp
counter). To keep the result accurate, we repeat the read if we detect
an overflow (i.e. the upper value varies). However, some hardware is just
plain flaky and may endless loop as the the upper 32bits are not stable.
Just give up after a couple of tries and report whatever we read last.

v2: Use the most recent values when erring out on an unstable register.

Reported-by: russianneuromancer@ya.ru
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91906Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

connector->encoder is initialized as NULL. Fix this by setting it in
during pre enable. MST connectors are not read out during initial hw
readout, and have no fixed encoder mappings. So it's harmless to
return false when the connector has never been assigned to an encoder.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NAnder Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Pass the correct hpd[] array to intel_get_hpd_pins() on pre-g4x
platforms.

This got broken in the following commit:
commit fd63e2a9
Author: Imre Deak <imre.deak@intel.com>
Date:   Tue Jul 21 15:32:44 2015 -0700

    drm/i915: combine i9xx_get_hpd_pins and pch_get_hpd_pins

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NEgbert Eich <eich@suse.de>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

commit 346add78
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Jul 14 18:07:30 2015 +0200

    drm/i915: Use expcitly fixed type in compat32 structs

changed the type of param field in drm_i915_getparam from int to
s32. This header is exported to userspace and needs to use userspace
type __s32 instead.

This fixes userspace compilation errors like the following:
include/drm/i915_drm.h:361:2: error: unknown type name 's32'
  s32 param;
Signed-off-by: NArtem Savkov <asavkov@redhat.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

There have been many hard to track down bugs whereby userspace forgot to
flag a write buffer and then cause graphics corruption or a hung GPU
when that buffer was later purged under memory pressure (as the buffer
appeared clean, its pages would have been evicted rather than preserved
and any changes more recent than in the backing storage would be lost).
In retrospect this is a rare optimisation against memory pressure,
already the slow path. If we always mark the buffer as dirty when
accessed by the GPU, anything not used can still be evicted cheaply
(ideal behaviour for mark-and-sweep eviction) but we do not run the risk
of corruption. For correct read serialisation, userspace still has to
notify when the GPU writes to an object. However, there are certain
situations under which userspace may wish to tell white lies to the
kernel...
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Kristian Høgsberg <krh@bitplanet.net>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: "Goel, Akash" <akash.goel@intel.co>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The DP MST encoder config function never sets ddi_pll_sel, even though
its value is programmed in its ->pre_enable() hook. That used to work
because a new pipe_config was kzalloc'ed at every modeset, and the value
of zero selects the highest clock for the PLL. Starting with the commit
below, the value of ddi_pll_sel is preserved through modesets, and since
the correct value wasn't properly setup by the MST code, it could lead
to warnings and blank screens.

commit 8504c74c
Author: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Date:   Fri May 15 11:51:50 2015 +0300

    drm/i915: Preserve ddi_pll_sel when allocating new pipe_config

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91628
Cc: stable@vger.kernel.org # 7e6313a2 drm/i915: Don't use link_bw for PLL setup
Cc: stable@vger.kernel.org
Cc: Timo Aaltonen <tjaalton@ubuntu.com>
Cc: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Use port_clock instead of link_bw when picking the PLL parameters for
DP. link_bw may be zero with an eDP 1.4 sink that supports
DP_LINK_RATE_SET so we shouldn't use it for anything other than feed it
to the sink appropriately.

v2: Fix typo in commit message (Sivakumar)
Reviewed-by: NSivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
[Jani: cherry-picked from future.]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Commit 92122789 ("drm/i915: preserve SSC if previously set v3")
added code to intel_modeset_gem_init to override the SSC status read
from VBT with the SSC status set by BIOS.

However, intel_modeset_gem_init is invoked *after* intel_modeset_init,
which calls intel_setup_outputs, which *modifies* SSC status by way of
intel_init_pch_refclk. So unlike advertised, intel_modeset_gem_init
doesn't preserve the SSC status set by BIOS but whatever
intel_init_pch_refclk decided on.

This is a problem on dual gpu laptops such as the MacBook Pro which
require either a handler to switch DDC lines, or the discrete gpu
to proxy DDC/AUX communication: Both the handler and the discrete
gpu may initialize after the i915 driver, and consequently, an LVDS
connector may initially seem disconnected and the SSC therefore
is disabled by intel_init_pch_refclk, but on reprobe the connector
may turn out to be connected and the SSC must then be enabled.

Due to 92122789 however, the SSC is not enabled on reprobe since
it is assumed BIOS disabled it while in fact it was disabled by
intel_init_pch_refclk.

Also, because the SSC status is preserved so late, the preserved value
only ever gets used on resume but not on panel initialization:
intel_modeset_init calls intel_init_display which indirectly calls
intel_panel_use_ssc via multiple subroutines, *before* the BIOS value
overrides the VBT value in intel_modeset_gem_init (intel_panel_use_ssc
is the sole user of dev_priv->vbt.lvds_use_ssc).

Fix this by moving the code introduced by 92122789 from
intel_modeset_gem_init to intel_modeset_init before the invocation
of intel_setup_outputs and intel_init_display.

Add a DRM_DEBUG_KMS as suggested way back by Jani:
http://lists.freedesktop.org/archives/intel-gfx/2014-June/046666.html

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115Tested-by: NPaul Hordiienko <pvt.gord@gmail.com>
    [MBP  6,2 2010  intel ILK + nvidia GT216  pre-retina]
Tested-by: NWilliam Brown <william@blackhats.net.au>
    [MBP  8,2 2011  intel SNB + amd turks     pre-retina]
Tested-by: NLukas Wunner <lukas@wunner.de>
    [MBP  9,1 2012  intel IVB + nvidia GK107  pre-retina]
Tested-by: NBruno Bierbaumer <bruno@bierbaumer.net>
    [MBP 11,3 2013  intel HSW + nvidia GK107  retina -- work in progress]
Fixes: 92122789 ("drm/i915: preserve SSC if previously set v3")
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

From B spec, DDI_E port belong to PowerWell 2, but
DDI_E share the powerwell_req/staus register bit with
DDI_A which belong to DDI_A_E_POWER_WELL.

In order to communicate with the connector on DDI-E, both
DDI_A_E_POWER_WELL and POWER_WELL_2 must be enabled.

Currently intel_dp_power_get(DDI_E) only enable
DDI_A_E_POWER_WELL, this patch will not only enable
DDI_a_E_POWER_WELL but also enable POWER_WELL_2.

This patch also fix the DDI-E hotplug function.
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Enable eDP on DDI-E.

Also let's remove duplicated definitions to avoid later confusion.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NXiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

There are OEMs using DDI-E out there,
so let's enable it.

Unfortunately there is no detection bit for DDI-E
So we need to rely on VBT for that.

I also need to give credits to Xiong since before seing
his approach to check info->support_* I was creating an ugly
vbt->ddie_sfuse_strap in order to propagate the ddi presence info

v2: Rebased as last patch in the series. since all other patches
in this series are needed for anything working propperly on DDI-E.

Credits-to: "Zhang, Xiong Y" <xiong.y.zhang@intel.com>
Cc: "Zhang, Xiong Y" <xiong.y.zhang@intel.com>
Reviewed-by: NXiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

DDI-E doesn't have the correspondent GMBUS pin.

We rely on VBT to tell us which one it being used instead.

The DVI/HDMI on shared port couldn't exist.

This patch isn't tested without hardware wchich has HDMI
on DDI-E.

v2: fix trailing whitespace
v3: MISSING_CASE take place of BUG()
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

commit da2bc1b9
Author: Imre Deak <imre.deak@intel.com>
Date:   Thu Oct 23 19:23:26 2014 +0300

    drm/i915: add poweroff_late handler

introduced a regression on old platforms during hibernation. A workaround was
added in

commit ab3be73f
Author: Imre Deak <imre.deak@intel.com>
Date:   Mon Mar 2 13:04:41 2015 +0200

    drm/i915: gen4: work around hang during hibernation

using an explicit blacklist for the GENs/BIOS vendors where the issue was
reported. Later there we had reports of the same failure on platforms not on
this list.

To my best knowledge the correct thing to do is still to put the device to PCI
D3 state during hibernation, see [1] and [2] for the reasons. This also aligns
with our future plans to unify more the runtime and system suspend/resume
paths. Since an exact blacklist seems to be impractical (multiple GENs and
BIOS vendors are affected) apply the workaround on everything pre GEN6.

[1] http://lists.freedesktop.org/archives/intel-gfx/2015-February/060710.html
[2] https://lkml.org/lkml/2015/6/22/274

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=95061Reported-by: NIlya Tumaykin <itumaykin@gmail.com>
Reported-by: NDirk Griesbach <spamthis@freenet.de>
Reported-by: NPavel Machek <pavel@ucw.cz>
Reported-by: NMikko Rapeli <mikko.rapeli@iki.fi>
Tested-by: NMikko Rapeli <mikko.rapeli@iki.fi>
Reported-by: NPaul Bolle <pebolle@tiscali.nl>
CC: stable@vger.kernel.org
Signed-off-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We are no longer checkling the DP link status on long hpd. We used to do
that from the .hot_plug() handler, but it was removed when MST got
introduced.

If there's no userspace we now fail to retrain the link if the sink
power is toggled (or cable yanked and replugged), meaning the user is
left staring at a blank screen. With the retraining put back that should
be fixed.

Also remove the leftover comment that referred to the old retraining
from .hot_plug().

Fixes a regression introduced in:
commit 0e32b39c
Author: Dave Airlie <airlied@redhat.com>
Date:   Fri May 2 14:02:48 2014 +1000

    drm/i915: add DP 1.2 MST support (v0.7)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89453Tested-by: NPalmer Dabbelt <palmer@dabbelt.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91407
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89461
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89594
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85641
Cc: Dave Airlie <airlied@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Since BIOS RC 1.4 it would enable CDCLK PLL during BIOS S3 resume, then
driver needs to set CDCLK to avoid display corruption if DPLL0 enabled.

References: https://bugs.freedesktop.org/show_bug.cgi?id=91697Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NCooper Chiou <cooper.chiou@intel.com>
Reviewed-by: NWei Shun Chang <wei.shun.chang@intel.com>
Tested-by: NGary Wang <gary.c.wang@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Gavin Hindman <gavin.hindman@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Xiong Y Zhang <xiong.y.zhang@intel.com>
Signed-off-by: NGary Wang <gary.c.wang@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

v2: fix one error found by checkpath.pl
v3: Add one ignored break for switch-case. DDI-E hotplug
    function doesn't work after updating drm-intel tree,
    I checked the code and found this missing which isn't
    the root cause for broke DDI-E hp.  The broken
    DDI-E hp function is fixed by "Adding DDI_E power
    well domain".
Signed-off-by: NXiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: NTimo Aaltonen <timo.aaltonen@canonical.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The gtt.stolen_size field is of type size_t, and so should be printed
using %zu to avoid build warnings on either 32-bit and 64-bit builds.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

SKL-Y can now use the same programming for all VccIO values after an
adjustment to I_boost.  SKL-U DP table adjustments.

1. Remove SKL Y 0.95V from "SKL H and S" columns in all tables. The
   other SKL Y column removes the "0.85V VccIO" so it now applies to all
   voltages.

2. DP table changes SKL U 400mV+0db dword 0 value from 2016h to 201Bh.

3. DP table changes SKL U 600mv+0db dword 0 value from 2016h to 201Bh.

4. DP table increases I_boost to level 3 for SKL Y 400mv+9.5db.

v2: Fix compilation warnings as pointed by Paulo.

Reference: Graphics Spec Change r97962
Cc: Arthur Runyan <arthur.j.runyan@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
[Jani: reformatted commit message for shorter lines.]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

VBT version 196 increased the size of common_child_dev_config. The
parser code assumed that the size of this structure would not change.

The modified code now copies the amount needed based on the VBT version,
and emits a debug message if the VBT version is unknown (too new); since
the struct config block won't shrink in newer versions it should be
harmless to copy the maximum known size in such cases, so that's what we
do, but emitting the warning is probably sensible anyway.

In the longer run it might make sense to modify the parser code to use a
version/feature mapping, rather than hardcoding things like this, but
for now the variants are fairly manageable.

This fixes a regression introduced in

commit 75067dde
Author: Antti Koskipaa <antti.koskipaa@linux.intel.com>
Date:   Fri Jul 10 14:10:55 2015 +0300

    drm/i915: Per-DDI I_boost override

since that commit changed the child device config size without updating
the checks and memcpy.

v2: Stricter size checks

v3 by Jani:
- Keep the checks strict, and warnigns verbose, but keep going anyway.
- Take care to copy the max amount of child device config we can.
- Fix the messages.
Signed-off-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

This patch fixes the bug that SKL SKUs before B0 might return
HBR2 as supported even though it is not supposed to be enabled
on such platforms.

v2: optimize if else condition (Jani)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NSivakumar Thulasimani <sivakumar.thulasimani@intel.com>
[Jani: minor whitespace fix.]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

commit 75067dde
Author: Antti Koskipaa <antti.koskipaa@linux.intel.com>
Date:   Fri Jul 10 14:10:55 2015 +0300

    drm/i915: Per-DDI I_boost override

increased size of union child_device_config without taking into account
the size check in parse_sdvo_device_mapping(). Switch the function over
to using the legacy struct only.

Fixes: 75067dde ("drm/i915: Per-DDI I_boost override")
Cc: Antti Koskipaa <antti.koskipaa@linux.intel.com>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Linux 4.2-rc8

Backmerge required for Intel so they can fix their -next tree up properly.

- Added PLL algorithm for a new rev of G200e
- Removed the bandwidth limitation for the new G200e
Signed-off-by: NMathieu Larouche <mathieu.larouche@matrox.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

- Added support for the new deviceID for G200eW3
- Added PLL algorithm for the G200eW3
- Added some initialization code for G200eW3
Signed-off-by: NMathieu Larouche <mathieu.larouche@matrox.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Pull SCSI fixes from James Bottomley:
 "A couple of major (hang and deadlock) fixes with fortunately fairly
  rare triggering conditions.  The PM oops is only really triggered by
  people using enclosure services (rare) and the fnic driver is mostly
  used in enterprise environments"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  SCSI: Fix NULL pointer dereference in runtime PM
  fnic: Use the local variable instead of I/O flag to acquire io_req_lock in fnic_queuecommand() to avoid deadloack

Pull MIPS bug fixes from Ralf Baechle:
 "Two more fixes for 4.2.

  One fixes a build issue with the LLVM assembler - LLVM assembler macro
  names are case sensitive, GNU as macro names are insensitive; the
  other corrects a license string (GPL v2, not GPLv2) such that the
  module loader will recognice the license correctly"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  FIRMWARE: bcm47xx_nvram: Fix module license.
  MIPS: Fix LLVM build issue.

Pull 9p regression fix from Al Viro:
 "Fix for breakage introduced when switching p9_client_{read,write}() to
  struct iov_iter * (went into 4.1)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: ensure err is initialized to 0 in p9_client_read/write

Some use of those functions were providing unitialized values to those
functions. Notably, when reading 0 bytes from an empty file on a 9P
filesystem, the return code of read() was not 0.

Tested with this simple program:

    #include <assert.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(int argc, const char **argv)
    {
        assert(argc == 2);
        char buffer[256];
        int fd = open(argv[1], O_RDONLY|O_NOCTTY);
        assert(fd >= 0);
        assert(read(fd, buffer, 0) == 0);
        return 0;
    }

Cc: stable@vger.kernel.org # v4.1
Signed-off-by: NVincent Bernat <vincent@bernat.im>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull ARM fixes from Russell King:
 "Another couple of small ARM fixes.

  A patch from Masahiro Yamada who noticed that "make -jN all zImage"
  would end up generating bad images where N > 1, and a patch from
  Nicolas to fix the Marvell CPU user access optimisation code when page
  faults are disabled"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8418/1: add boot image dependencies to not generate invalid images
  ARM: 8414/1: __copy_to_user_memcpy: fix mmap semaphore usage

Pull x86 fixes from Ingo Molnar:
 "Various low level fixes: fix more fallout from the FPU rework and the
  asm entry code rework, plus an MSI rework fix, and an idle-tracing fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/math-emu: Fix crash in fork()
  x86/fpu/math-emu: Fix math-emu boot crash
  x86/idle: Restore trace_cpu_idle to mwait_idle() calls
  x86/irq: Build correct vector mapping for multiple MSI interrupts
  Revert "sched/x86_64: Don't save flags on context switch"

Pull perf fixes from Ingo Molnar:
 "Tooling fixes: a 'perf record' deadlock fix plus debuggability fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf top: Show backtrace when handling a SIGSEGV on --stdio mode
  perf tools: Fix buildid processing
  perf tools: Make fork event processing more resilient
  perf tools: Avoid deadlock when map_groups are broken

Pull irq fixes from Thomas Gleixner:
 "A series of small fixlets for a regression visible on OMAP devices
  caused by the conversion of the OMAP interrupt chips to hierarchical
  interrupt domains.  Mostly one liners on the driver side plus a small
  helper function in the core to avoid open coded mess in the drivers"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/crossbar: Restore set_wake functionality
  irqchip/crossbar: Restore the mask on suspend behaviour
  ARM: OMAP: wakeupgen: Restore the irq_set_type() mechanism
  irqchip/crossbar: Restore the irq_set_type() mechanism
  genirq: Introduce irq_chip_set_type_parent() helper
  genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

Pull timer fixes from Thomas Gleixner:
 "Two minimalistic fixes for 4.2 regressions:

   - Eric fixed a thinko in the timer_list base switching code caused by
     the overhaul of the timer wheel.  It can cause a cpu to see the
     wrong base for a timer while we move the timer around.

   - Guenter fixed a regression for IMX if booted w/o device tree, where
     the timer interrupt is not initialized and therefor the machine
     fails to boot"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/imx: Fix boot with non-DT systems
  timer: Write timer->flags atomically

During later stages of math-emu bootup the following crash triggers:

	 math_emulate: 0060:c100d0a8
	 Kernel panic - not syncing: Math emulation needed in kernel
	 CPU: 0 PID: 1511 Comm: login Not tainted 4.2.0-rc7+ #1012
	 [...]
	 Call Trace:
	  [<c181d50d>] dump_stack+0x41/0x52
	  [<c181c918>] panic+0x77/0x189
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c164c2d7>] math_emulate+0xba7/0xbd0
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c1109c3c>] ? __alloc_pages_nodemask+0x12c/0x870
	  [<c136ac20>] ? proc_clear_tty+0x40/0x70
	  [<c136ac6e>] ? session_clear_tty+0x1e/0x30
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c1003575>] do_device_not_available+0x45/0x70
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c18258e6>] error_code+0x5a/0x60
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c100c205>] arch_dup_task_struct+0x25/0x30
	  [<c1048cea>] copy_process.part.51+0xea/0x1480
	  [<c115a8e5>] ? dput+0x175/0x200
	  [<c136af70>] ? no_tty+0x30/0x30
	  [<c1157242>] ? do_vfs_ioctl+0x322/0x540
	  [<c104a21a>] _do_fork+0xca/0x340
	  [<c1057b06>] ? SyS_rt_sigaction+0x66/0x90
	  [<c104a557>] SyS_clone+0x27/0x30
	  [<c1824a80>] sysenter_do_call+0x12/0x12

The reason is the incorrect assumption in fpu_copy(), that FNSAVE
can be executed from math-emu kernels as well.

Don't try to copy the registers, the soft state will be copied
by fork anyway, so the child task inherits the parent task's
soft math state.

With this fix applied math-emu kernels boot up fine on modern
hardware and the 'no387 nofxsr' boot options.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

On a math-emu bootup the following crash occurs:

	Initializing CPU#0
	------------[ cut here ]------------
	kernel BUG at arch/x86/kernel/traps.c:779!
	invalid opcode: 0000 [#1] SMP
	[...]
	EIP is at do_device_not_available+0xe/0x70
	[...]
	Call Trace:
	 [<c18238e6>] error_code+0x5a/0x60
	 [<c1002bd0>] ? math_error+0x140/0x140
	 [<c100bbd9>] ? fpu__init_cpu+0x59/0xa0
	 [<c1012322>] cpu_init+0x202/0x330
	 [<c104509f>] ? __native_set_fixmap+0x1f/0x30
	 [<c1b56ab0>] trap_init+0x305/0x346
	 [<c1b548af>] start_kernel+0x1a5/0x35d
	 [<c1b542b4>] i386_start_kernel+0x82/0x86

The reason is that in the following commit:

  b1276c48 ("x86/fpu: Initialize fpregs in fpu__init_cpu_generic()")

I failed to consider math-emu's limitation that it cannot execute the
FNINIT instruction in kernel mode.

The long term fix might be to allow math-emu to execute (certain) kernel
mode FPU instructions, but for now apply the safe (albeit somewhat ugly)
fix: initialize the emulation state explicitly without trapping out to
the FPU emulator.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

While the idea behind get_maintainer seems highly useful it's
unfortunately way to trigger happy to grab people that once had a few
commits to files.  For someone like me who does a lot of tree-wide API
work that leads to an incredible amount of Cc spam.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>