Changing an inode's metadata may result in our not needing to appraise
the file.  In such cases, we must remove 'security.ima'.

Changelog v1:
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

For performance, replace the iint spinlock with rwlock/read_lock.

Eric Paris questioned this change, from spinlocks to rwlocks, saying
"rwlocks have been shown to actually be slower on multi processor
systems in a number of cases due to the cache line bouncing required."

Based on performance measurements compiling the kernel on a cold
boot with multiple jobs with/without this patch, Dmitry Kasatkin
and I found that rwlocks performed better than spinlocks, but very
insignificantly.  For example with total compilation time around 6
minutes, with rwlocks time was 1 - 3 seconds shorter... but always
like that.

Changelog v2:
- new patch taken from the 'allocating iint improvements' patch
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

With IMA-appraisal's removal of the iint mutex and taking the i_mutex
instead, allocating the iint becomes a lot simplier, as we don't need
to be concerned with two processes racing to allocate the iint. This
patch cleans up and improves performance for allocating the iint.

- removed redundant double i_mutex locking
- combined iint allocation with tree search

Changelog v2:
- removed the rwlock/read_lock changes from this patch
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

Unlike the IMA measurement policy, the appraise policy can not be dependent
on runtime process information, such as the task uid, as the 'security.ima'
xattr is written on file close and must be updated each time the file changes,
regardless of the current task uid.

This patch extends the policy language with 'fowner', defines an appraise
policy, which appraises all files owned by root, and defines 'ima_appraise_tcb',
a new boot command line option, to enable the appraise policy.

Changelog v3:
- separate the measure from the appraise rules in order to support measuring
  without appraising and appraising without measuring.
- change appraisal default for filesystems without xattr support to fail
- update default appraise policy for cgroups

Changelog v1:
- don't appraise RAMFS (Dmitry Kasatkin)
- merged rest of "ima: ima_must_appraise_or_measure API change" commit
  (Dmtiry Kasatkin)

  ima_must_appraise_or_measure() called ima_match_policy twice, which
  searched the policy for a matching rule.  Once for a matching measurement
  rule and subsequently for an appraisal rule. Searching the policy twice
  is unnecessary overhead, which could be noticeable with a large policy.

  The new version of ima_must_appraise_or_measure() does everything in a
  single iteration using a new version of ima_match_policy().  It returns
  IMA_MEASURE, IMA_APPRAISE mask.

  With the use of action mask only one efficient matching function
  is enough.  Removed other specific versions of matching functions.

Changelog:
- change 'owner' to 'fowner' to conform to the new LSM conditions posted by
  Roberto Sassu.
- fix calls to ima_log_string()
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

IMA currently maintains an integrity measurement list used to assert the
integrity of the running system to a third party.  The IMA-appraisal
extension adds local integrity validation and enforcement of the
measurement against a "good" value stored as an extended attribute
'security.ima'.  The initial methods for validating 'security.ima' are
hashed based, which provides file data integrity, and digital signature
based, which in addition to providing file data integrity, provides
authenticity.

This patch creates and maintains the 'security.ima' xattr, containing
the file data hash measurement.  Protection of the xattr is provided by
EVM, if enabled and configured.

Based on policy, IMA calls evm_verifyxattr() to verify a file's metadata
integrity and, assuming success, compares the file's current hash value
with the one stored as an extended attribute in 'security.ima'.

Changelov v4:
- changed iint cache flags to hex values

Changelog v3:
- change appraisal default for filesystems without xattr support to fail

Changelog v2:
- fix audit msg 'res' value
- removed unused 'ima_appraise=' values

Changelog v1:
- removed unused iint mutex (Dmitry Kasatkin)
- setattr hook must not reset appraised (Dmitry Kasatkin)
- evm_verifyxattr() now differentiates between no 'security.evm' xattr
  (INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the
  'security.evm' (INTEGRITY_NOXATTRS).
- replace hash_status with ima_status (Dmitry Kasatkin)
- re-initialize slab element ima_status on free (Dmitry Kasatkin)
- include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA
- merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin)
- removed unnecessary error variable in process_measurement() (Dmitry Kasatkin)
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
  (moved ima_inode_post_setattr() to ima_appraise.c)
- make sure ima_collect_measurement() can read file

Changelog:
- add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin)
- fix the race condition between chmod, which takes the i_mutex and then
  iint->mutex, and ima_file_free() and process_measurement(), which take
  the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin)
- cleanup of ima_appraise_measurement() (Dmitry Kasatkin)
- changes as a result of the iint not allocated for all regular files, but
  only for those measured/appraised.
- don't try to appraise new/empty files
- expanded ima_appraisal description in ima/Kconfig
- IMA appraise definitions required even if IMA_APPRAISE not enabled
- add return value to ima_must_appraise() stub
- unconditionally set status = INTEGRITY_PASS *after* testing status,
  not before.  (Found by Joe Perches)
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

ima_file_free(), called on __fput(), currently flags files that have
changed, so that the file is re-measured.  For appraising a files's
integrity, the file's hash must be re-calculated and stored in the
'security.ima' xattr to reflect any changes.

This patch moves the ima_file_free() call to before releasing the file
in preparation of ima-appraisal measuring the file and updating the
'security.ima' xattr.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

This patch takes the i_mutex lock before security_inode_removexattr(),
instead of after, in preparation of calling ima_inode_removexattr().
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>

When running a 64-bit kernel and receiving prctls from a 32-bit
userspace, the "-1" used as an unsigned long will end up being
misdetected. The kernel is looking for 0xffffffffffffffff instead of
0xffffffff. Since prctl lacks a distinct compat interface, Yama needs
to handle this translation itself. As such, support either value as
meaning PR_SET_PTRACER_ANY, to avoid breaking the ABI for 64-bit.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>

Unconditionally call Yama when CONFIG_SECURITY_YAMA_STACKED is selected,
no matter what LSM module is primary.

Ubuntu and Chrome OS already carry patches to do this, and Fedora
has voiced interest in doing this as well. Instead of having multiple
distributions (or LSM authors) carrying these patches, just allow Yama
to be called unconditionally when selected by the new CONFIG.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

This patch declares the internal struct and functions as static to provide
more security.
Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

The Physical Presence Interface enables the OS and the BIOS to cooperate and
provides a simple and straightforward platform user experience for
administering the TPM without sacrificing security.

V2: separate the patch out in a separate source file,
    add #ifdef CONFIG_ACPI so it compiles out on ppc,
    use standard error instead of ACPI error as return code of show/store fns.
V3: move #ifdef CONFIG_ACPI from .c file to .h file.
V4: move tpm_ppi code from tpm module to tpm_bios module.
V5: modify sys_add_ppi() so that ppi_attr_grp doesn't need to be exported
Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

In drivers/char/tpm/tpm_acpi.c::read_log() we call
acpi_os_map_memory(). That call may fail for a number of reasons
(invalid address, out of memory etc). If the call fails it returns
NULL and we just pass that to memcpy() unconditionally, which will go
bad when it tries to dereference the pointer.

Unfortunately we just get NULL back, so we can't really tell the user
exactely what went wrong, but we can at least avoid crashing and
return an error (-EIO seemed more generic and more suitable here than
-ENOMEM or something else, so I picked that).
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Enable tpm_ibmvtpm driver by default when IMA is enabled on PPC64
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

This patch retrieves the event log data from the device tree
during file open. The event log data will then displayed through
securityfs.
Signed-off-by: Ashley Lai <adlai@us.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

This patch instantiate Stored Measurement Log (SML) and put the
log address and size in the device tree.
Signed-off-by: Ashley Lai <adlai@us.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

This patch adds a new device driver to support IBM virtual TPM
(vTPM) for PPC64.  IBM vTPM is supported through the adjunct
partition with firmware release 740 or higher.  With vTPM
support, each lpar is able to have its own vTPM without the
physical TPM hardware.

This driver provides TPM functionalities by communicating with
the vTPM adjunct partition through Hypervisor calls (Hcalls)
and Command/Response Queue (CRQ) commands.
Signed-off-by: Ashley Lai <adlai@us.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

The tpm_tis driver doesn't use tpm_tis_resume except when PM is
configured and doesn't make use of tpm_tis_reenable_interrupts except
when PM or PNP is configured.
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Moved the atomic_set of the data_pending variable until after the
tpm_read has completed processing. The existing code had a window of
time where a second write to the driver could clobber the tpm command
buffer.

Also fixed an issue where if close was called on the tpm device before a
read completed, the tpm command buffer would be returned to the OS,
which could contain sensitive information.
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

This driver will make use of any available TPM chip on the system as a
hwrng source.
Acked-by: David Safford <safford@linux.vnet.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Move the tpm_get_random api from the trusted keys code into the TPM
device driver itself so that other callers can make use of it. Also,
change the api slightly so that the number of bytes read is returned in
the call, since the TPM command can potentially return fewer bytes than
requested.
Acked-by: David Safford <safford@linux.vnet.ibm.com>
Reviewed-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Break ACPI-specific pieces of the event log handling into their own file
and create tpm_eventlog.[ch] to store common event log handling code.
This will be required to integrate future event log sources on platforms
without ACPI tables.
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

This patch adds a driver to support Infineon's SLB 9635 TT 1.2 Soft I2C TPMs
which follow the TGC TIS 1.2 TPM specification[1] and Infineon's I2C Protocol
Stack Specification 0.20.
The I2C Protocol Stack Specification is a simple adaption of the LPC TIS
Protocol to the I2C Bus.
The I2C TPMs can be used when LPC Bus is not available (i.e. non x86
architectures like ARM).

The driver is based on the tpm_tis.c driver by Leendert van Dorn and Kyleen
Hall and has quite similar functionality.

Tested on Nvidia ARM Tegra2 Development Platform and Beagleboard (ARM OMAP)
Tested with the Trousers[2] TSS API Testsuite v 0.3 [3]
Compile-tested on x86 (32/64-bit)

Updates since version 2.1.4:
- included "Lock the I2C adapter for a sequence of requests", by Bryan Freed
- use __i2c_transfer instead of own implementation of unlocked i2c_transfer
- use struct dev_pm_ops for power management via SIMPLE_DEV_PM_OPS

Updates since version 2.1.3:
- use proper probing mechanism
* either add the tpm using I2C_BOARD_INFO to your board file or probe it
* during runtime e.g on BeagleBoard using :
* "echo tpm_i2c_infineon 0x20 > /sys/bus/i2c/devices/i2c-2/new_device"
- fix possible endless loop if hardware misbehaves
- improved return codes
- consistent spelling i2c/tpm -> I2C/TPM
- remove hardcoded sleep values and msleep usage
- removed debug statements
- added check for I2C functionality
- renaming to tpm_i2c_infineon

Updates since version 2.1.2:
- added sysfs entries for duration and timeouts
- updated to new tpm_do_selftest

Updates since version 2.1.0:
- improved error handling
- implemented workarounds needed by the tpm
- fixed typos

References:
[1]
http://www.trustedcomputinggroup.org/resources/pc_client_work_group_pc_client_
specific_tpm_interface_specification_tis_version_12/
[2] http://trousers.sourceforge.net/
[3]
http://sourceforge.net/projects/trousers/files/TSS%20API%20test%20suite/0.3/Reviewed-by: Andi Shyti <andi.shyti@gmail.com>
Acked-by: Marcel Selhorst <tpmdd@selhorst.net>
Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
Signed-off-by: Bryan Freed <bfreed@chromium.org>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Linux 3.6-rc2

Resync with Linus.

Following a report of a crash during an automount expire I found that
the locking in fs/autofs4/expire.c:get_next_positive_subdir() was wrong.
Not only is the locking wrong but the function is more complex than it
needs to be.

The function is meant to calculate (and dget) the next entry in the list
of directories contained in the root of an autofs mount point (an autofs
indirect mount to be precise). The main problem was that the d_lock of
the owner of the list was not being taken when walking the list, which
lead to list corruption under load. The only other lock that needs to
be taken is against the next dentry candidate so it can be checked for
usability.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull VFIO fix from Alex Williamson:
 "Just a trivial patch to include vfio.h in the installed headers so we
  can complete userspace integration into QEMU."

* tag 'vfio-for-v3.6-rc1' of git://github.com/awilliam/linux-vfio:
  vfio: Include vfio.h in installed headers

Pull fuse updates from Miklos Szeredi.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: verify all ioctl retry iov elements
  fuse: add missing INIT flag descriptions
  fuse: add missing INIT flags
  fuse: update attributes on aio_read
  fuse: invalidate inode mapping if mtime changes
  fuse: add FUSE_AUTO_INVAL_DATA init flag

Merge tag 'stable/for-linus-3.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fix from Konrad Rzeszutek Wilk:
 "Way back in v3.5 we added a mechanism to populate back pages that were
  released (they overlapped with MMIO regions), but neglected to reserve
  the proper amount of virtual space for extend_brk to work properly.

  Coincidentally some other commit aligned the _brk space to larger area
  so I didn't trigger this until it was run on a machine with more than
  2GB of MMIO space."

 * On machines with large MMIO/PCI E820 spaces we fail to boot b/c
   we failed to pre-allocate large enough virtual space for extend_brk.

* tag 'stable/for-linus-3.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/p2m: Reserve 8MB of _brk space for P2M leafs when populating back.

Pull SuperH fixes from Paul Mundt.

* tag 'sh-for-linus' of git://github.com/pmundt/linux-sh:
  sh: intc: Handle domain association for sparseirq pre-allocated vectors.
  sh: sh7269: Fix LCD pinmux
  sh: dma: fix request_irq usage

Moved to djbw@fb.com

Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Dan Williams <djbw@fb.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When dumping "Code: " sections from an oops, the trapping instruction
%rip points to can be a string copy

  2b:*  f3 a5                   rep movsl %ds:(%rsi),%es:(%rdi)

and the line contain a bunch of ":".  Current "cut" selects only the and
the second field output looks funnily overlaid this:

  2b:*  f3 a5                   rep movsl %ds     <-- trapping instruction:(%rsi),%es:(%rdi

Fix this by selecting the remaining fields too.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull two slave-dmaengine fixes from Vinod Koul:
 "One fixes the correct use of clock API in imx driver and the other
  enables clock for tegra driver, which is used for other tegra driver
  conversion to dmanegine in -next."

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: tegra: enable/disable dma clock
  dma: imx-dma: Fix kernel crash due to missing clock conversion

Pull more drm fixes from Dave Airlie:
 "Just some intel and nouveau ones this time, intel has more edp panel
  fixes for macbooks and nouveau has a suspend/resume regression fix in
  there."

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: Apply post-sync write for pipe control invalidates
  drm/i915: reorder edp disabling to fix ivb MacBook Air
  drm/nv86/fifo: suspend fix
  drm/nouveau: disable copy engine on NVAF
  nouveau: fixup scanout enable in nvc0_pm
  drm/nouveau/aux: mask off higher bits of auxch index in i2c table entry
  drm/nvd0/disp: mask off high 16 bit of negative cursor x-coordinate
  drm/i915: ensure i2c adapter is all set before adding it
  drm/i915: ignore eDP bpc settings from vbt
  drm/i915: Fix blank panel at reopening lid
  drm/nve0/fifo: add support for the flip completion swmthd

Pull two sparc fixes from David S. Miller.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Be less verbose during vmemmap population.
  sparc64: do not clobber personality flags in sys_sparc64_personality()

* 'drm-nouveau-fixes' of git://git.freedesktop.org/git/nouveau/linux-2.6:
  drm/nv86/fifo: suspend fix
  drm/nouveau: disable copy engine on NVAF
  nouveau: fixup scanout enable in nvc0_pm
  drm/nouveau/aux: mask off higher bits of auxch index in i2c table entry
  drm/nvd0/disp: mask off high 16 bit of negative cursor x-coordinate
  drm/nve0/fifo: add support for the flip completion swmthd

Daniel Vetter writes:

"A few important fixers:
- fix various lvds backlight issues, regressed in 3.6 (Takashi Iwai)
- make the retina mbp work (ignore bogus edp bpc value in vbt)
- fix a gmbus regression introduced in (iirc) 3.4 (Jani Nikula)
- fix an edp panel power sequence regression, fixes the new macbook air
- apply the tlb invalidate w/a

Otherwise we still have another gmbus regression (patches are awaiting
tested-bys) and there's something odd going with some rare systems not
entering rc6 often enough (and hence blowing through too much power).  It
seems to be a timing-related issue and can be mitigated by frobbing the
magic tuning parameters. We're still working on that one. Also, we still
have some fallout from the hw context support, but you can only hit that
with mesa master."

* 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel:
  drm/i915: Apply post-sync write for pipe control invalidates
  drm/i915: reorder edp disabling to fix ivb MacBook Air
  drm/i915: ensure i2c adapter is all set before adding it
  drm/i915: ignore eDP bpc settings from vbt
  drm/i915: Fix blank panel at reopening lid

On a 2-node machine with 256GB of ram we get 512 lines of
console output, which is just too much.

This mimicks Yinghai Lu's x86 commit c2b91e2e
(x86_64/mm: check and print vmemmap allocation continuous) except that
we aren't ever going to get contiguous block pointers in between calls
so just print when the virtual address or node changes.

This decreases the output by an order of 16.

Also demote this to KERN_DEBUG.
Signed-off-by: David S. Miller <davem@davemloft.net>

When invalidating the TLBs it is documentated as requiring a post-sync
write. Failure to do so seems to result in a GPU hang.

Exposure to this hang on IVB seems to be a result of removing the extra
stalls required for SNB pipecontrol workarounds:

commit 6c6cf5aa
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jul 20 18:02:28 2012 +0100

    drm/i915: Only apply the SNB pipe control w/a to gen6

Note: Manually switch the pipe_control cmd to 4 dwords to avoid a
(silent) functional conflict with -next. This way will get a loud (but
conflict with next (since the scratch_addr has been deleted there).

Reported-and-tested-by: yex.tian@intel.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=53322Acked-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: added note about merge conflict with -next.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

eDP is tons of fun. It turns out that at least the new MacBook Air 5,1
model absolutely doesn't like the new force vdd dance we've introduced
in

commit 6cb49835
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Sun May 20 17:14:50 2012 +0200

    drm/i915: enable vdd when switching off the eDP panel

But that patch also tried to fix some neat edp sequence issue with the
force_vdd timings. Closer inspection reveals that we've raised
force_vdd only to do the aux channel communication dp_sink_dpms. If we
move the edp_panel_off below that, we don't need any force_vdd for the
disable sequence, which makes the Air happy.

Unfortunately the reporter of the original bug that the above commit
fixed is travelling, so we can't test whether this regresses things.
But my theory is that since we don't check for any power-off ->
force_vdd-on delays in edp_panel_vdd_on, this was the actual
root-cause of this failure. With that force_vdd dance completely
eliminated, I'm hopeful the original bug stays fixed, too.

For reference the old bug, which hopefully doesn't get broken by this:

https://bugzilla.kernel.org/show_bug.cgi?id=43163

In any case, regression fixers win over plain bugfixes, so this needs
to go in asap.

v2: The crucial pieces seems to be to clear the force_vdd flag
uncoditionally, too, in edp_panel_off. Looks like this is left behind
by the firmware somehow.

v3: The Apple firmware seems to switch off the panel on it's own, hence
we still need to keep force_vdd on, but properly clear it when switching
the panel off.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=45671Tested-by: Roberto Romer <sildurin@gmail.com>
Tested-by: Daniel Wagner <wagi@monom.org>
Tested-by: Keith Packard <keithp@keithp.com>
Cc: stable@vger.kernel.org
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>