I've seen a fair number of issues with kswapd and other processes
appearing to get stuck in v3.12-rc.  Using sysrq-p many times seems to
indicate that it gets stuck somewhere in list_lru_walk_node(), called
from prune_icache_sb() and super_cache_scan().

I never seem to be able to trigger a calltrace for functions above that
point.

So I decided to add the following to super_cache_scan():

    @@ -81,10 +81,14 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
            inodes = list_lru_count_node(&sb->s_inode_lru, sc->nid);
            dentries = list_lru_count_node(&sb->s_dentry_lru, sc->nid);
            total_objects = dentries + inodes + fs_objects + 1;
    +printk("%s:%u: %s: dentries %lu inodes %lu total %lu\n", current->comm, current->pid, __func__, dentries, inodes, total_objects);

            /* proportion the scan between the caches */
            dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
            inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
    +printk("%s:%u: %s: dentries %lu inodes %lu\n", current->comm, current->pid, __func__, dentries, inodes);
    +BUG_ON(dentries == 0);
    +BUG_ON(inodes == 0);

            /*
             * prune the dcache first as the icache is pinned by it, then
    @@ -99,7 +103,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
                    freed += sb->s_op->free_cached_objects(sb, fs_objects,
                                                           sc->nid);
            }
    -
    +printk("%s:%u: %s: dentries %lu inodes %lu freed %lu\n", current->comm, current->pid, __func__, dentries, inodes, freed);
            drop_super(sb);
            return freed;
     }

and shortly thereafter, having applied some pressure, I got this:

    update-apt-xapi:1616: super_cache_scan: dentries 25632 inodes 2 total 25635
    update-apt-xapi:1616: super_cache_scan: dentries 1023 inodes 0
    ------------[ cut here ]------------
    Kernel BUG at c0101994 [verbose debug info unavailable]
    Internal error: Oops - BUG: 0 [#3] SMP ARM
    Modules linked in: fuse rfcomm bnep bluetooth hid_cypress
    CPU: 0 PID: 1616 Comm: update-apt-xapi Tainted: G      D      3.12.0-rc7+ #154
    task: daea1200 ti: c3bf8000 task.ti: c3bf8000
    PC is at super_cache_scan+0x1c0/0x278
    LR is at trace_hardirqs_on+0x14/0x18
    Process update-apt-xapi (pid: 1616, stack limit = 0xc3bf8240)
    ...
    Backtrace:
      (super_cache_scan) from [<c00cd69c>] (shrink_slab+0x254/0x4c8)
      (shrink_slab) from [<c00d09a0>] (try_to_free_pages+0x3a0/0x5e0)
      (try_to_free_pages) from [<c00c59cc>] (__alloc_pages_nodemask+0x5)
      (__alloc_pages_nodemask) from [<c00e07c0>] (__pte_alloc+0x2c/0x13)
      (__pte_alloc) from [<c00e3a70>] (handle_mm_fault+0x84c/0x914)
      (handle_mm_fault) from [<c001a4cc>] (do_page_fault+0x1f0/0x3bc)
      (do_page_fault) from [<c001a7b0>] (do_translation_fault+0xac/0xb8)
      (do_translation_fault) from [<c000840c>] (do_DataAbort+0x38/0xa0)
      (do_DataAbort) from [<c00133f8>] (__dabt_usr+0x38/0x40)

Notice that we had a very low number of inodes, which were reduced to
zero my mult_frac().

Now, prune_icache_sb() calls list_lru_walk_node() passing that number of
inodes (0) into that as the number of objects to scan:

    long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
                         int nid)
    {
            LIST_HEAD(freeable);
            long freed;

            freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate,
                                           &freeable, &nr_to_scan);

which does:

    unsigned long
    list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
                       void *cb_arg, unsigned long *nr_to_walk)
    {

            struct list_lru_node    *nlru = &lru->node[nid];
            struct list_head *item, *n;
            unsigned long isolated = 0;

            spin_lock(&nlru->lock);
    restart:
            list_for_each_safe(item, n, &nlru->list) {
                    enum lru_status ret;

                    /*
                     * decrement nr_to_walk first so that we don't livelock if we
                     * get stuck on large numbesr of LRU_RETRY items
                     */
                    if (--(*nr_to_walk) == 0)
                            break;

So, if *nr_to_walk was zero when this function was entered, that means
we're wanting to operate on (~0UL)+1 objects - which might as well be
infinite.

Clearly this is not correct behaviour.  If we think about the behaviour
of this function when *nr_to_walk is 1, then clearly it's wrong - we
decrement first and then test for zero - which results in us doing
nothing at all.  A post-decrement would give the desired behaviour -
we'd try to walk one object and one object only if *nr_to_walk were one.

It also gives the correct behaviour for zero - we exit at this point.

Fixes: 5cedf721 ("list_lru: fix broken LRU_RETRY behaviour")
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
[ Modified to make sure we never underflow the count: this function gets
  called in a loop, so the 0 -> ~0ul transition is dangerous  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull serial fixes from Greg KH:
 "Here are 3 tiny fixes that are needed for 3.12-final for some serial
  drivers.

  One of them is a revert of a broken patch, and two others are fixes
  for reported bugs.  All of these have been in linux-next for a while,
  I forgot I had not sent them to you yet, my fault"

(Actually, Greg, you _had_ sent two of the three, so this pulls in just
one actual new fix)

* tag 'tty-3.12-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty/serial: at91: fix uart/usart selection for older products

Pull drm fixes from Dave Airlie:
 "Mainly Intel regression fixes and quirks, along with a simple one
  liner to fix rendernodes ioctl access (off by default, but testers
  want to test it)"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm: allow DRM_IOCTL_VERSION on render-nodes
  drm/i915: Fix the PPT fdi lane bifurcate state handling on ivb
  drm/i915: No LVDS hardware on Intel D410PT and D425KT
  drm/i915/dp: workaround BIOS eDP bpp clamping issue
  drm/i915: Add HSW CRT output readout support
  drm/i915: Add support for pipe_bpp readout

Pull sound fixes from Takashi Iwai:
 "A few small HD-audio regression fixes, mostly for stable kernels, too"

* tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - Fix silent headphone on Thinkpads with AD1984A codec
  ALSA: hda - Add missing initial vmaster hook at build_controls callback
  ALSA: hda - Fix unbalanced runtime PM refcount after S3/S4

Pull KVM fixes from Paolo Bonzini:
 "Fixes for the 3.12 debugfs problem - removing the duplicate directory
  name, and using a better the error code"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: use a more sensible error number when debugfs directory creation fails
  KVM: Fix modprobe failure for kvm_intel/kvm_amd

The icount.reserved[] array isn't initialized so it leaks stack
information to userspace.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The DevInfo.u32Reserved[] array isn't initialized so it leaks kernel
information to user space.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We need to check the length parameter before doing the memcpy().  I've
actually changed it to strlcpy() as well so that it's NUL terminated.

You need CAP_NET_ADMIN to trigger these so it's not the end of the
world.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In commit d496f94d ('[SCSI] aacraid: fix security weakness') we
added a check on CAP_SYS_RAWIO to the ioctl.  The compat ioctls need the
check as well.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We need to check "count" so we don't overflow the ei->data buffer.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We don't cap the size of buffer from the user so we could write past the
end of the array here.  Only root can write to this file.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I don't know if this was due to cut and paste, or somebody was really
using a D20 to pick the error code for kvm_init_debugfs as suggested by
Linus (EFAULT is 14, so the possibility cannot be entirely ruled out).

In any case, this patch fixes it.
Reported-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The x86 specific kvm init creates a new conflicting
debugfs directory which causes modprobe issues
with kvm_intel and kvm_amd. For example,

sudo modprobe kvm_amd
modprobe: ERROR: could not insert 'kvm_amd': Bad address

The simplest fix is to just rename the directory. The following
KVM config options are set:

CONFIG_KVM_GUEST=y
CONFIG_KVM_DEBUG_FS=y
CONFIG_HAVE_KVM=y
CONFIG_HAVE_KVM_IRQCHIP=y
CONFIG_HAVE_KVM_IRQ_ROUTING=y
CONFIG_HAVE_KVM_EVENTFD=y
CONFIG_KVM_APIC_ARCHITECTURE=y
CONFIG_KVM_MMIO=y
CONFIG_KVM_ASYNC_PF=y
CONFIG_HAVE_KVM_MSI=y
CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT=y
CONFIG_KVM=m
CONFIG_KVM_INTEL=m
CONFIG_KVM_AMD=m
CONFIG_KVM_DEVICE_ASSIGNMENT=y

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
[Change debugfs directory name. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

DRM_IOCTL_VERSION is a reliable way to get the driver-name and version
information. It's not related to the interface-version (SET_VERSION ioctl)
so we can safely enable it on render-nodes.

Note that gbm uses udev-BUSID to load the correct mesa driver. However,
the VERSION ioctl should be the more reliable way to do this (in case we
add new DRM-bus drivers which have no BUSID or similar).
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Merge tag 'drm-intel-fixes-2013-10-29' of git://people.freedesktop.org/~danvet/drm-intel into drm-fixes

Regression and warn fixes for i915.

* tag 'drm-intel-fixes-2013-10-29' of git://people.freedesktop.org/~danvet/drm-intel:
  drm/i915: Fix the PPT fdi lane bifurcate state handling on ivb
  drm/i915: No LVDS hardware on Intel D410PT and D425KT
  drm/i915/dp: workaround BIOS eDP bpp clamping issue
  drm/i915: Add HSW CRT output readout support
  drm/i915: Add support for pipe_bpp readout

Nico Golde reports a few straggling uses of [io_]remap_pfn_range() that
really should use the vm_iomap_memory() helper.  This trivially converts
two of them to the helper, and comments about why the third one really
needs to continue to use remap_pfn_range(), and adds the missing size
check.
Reported-by: Nico Golde <nico@ngolde.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org.

Pull perf tooling fixes from Ingo Molnar:
 "This contains five tooling fixes:

   - fix a remaining mmap2 assumption which resulted in perf top output
     breakage
   - fix mmap ring-buffer processing bug that corrupts data
   - fix for a severe python scripting memory leak
   - fix broken (and user-visible) -g option handling
   - fix stdio output

  The diffstat size is larger than what we'd like to see this late :-/"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Fixup mmap event consumption
  perf top: Split -G and --call-graph
  perf record: Split -g and --call-graph
  perf hists: Add color overhead for stdio output buffer
  perf tools: Fix up /proc/PID/maps parsing
  perf script python: Fix mem leak due to missing Py_DECREFs on dict entries

Without the timer debugging, the delayed kobject release will just
result in undebuggable oopses if it triggers any latent bugs.  That
doesn't actually help debugging at all.

So make DEBUG_KOBJECT_RELEASE depend on DEBUG_OBJECTS_TIMERS to avoid
having people enable one without the other.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Originally I've thought that this is leftover hw state dirt from the
BIOS. But after way too much helpless flailing around on my part I've
noticed that the actual bug is when we change the state of an already
active pipe.

For example when we change the fdi lines from 2 to 3 without switching
off outputs in-between we'll never see the crucial on->off transition
in the ->modeset_global_resources hook the current logic relies on.

Patch version 2 got this right by instead also checking whether the
pipe is indeed active. But that in turn broke things when pipes have
been turned off through dpms since the bifurcate enabling is done in
the ->crtc_mode_set callback.

To address this issues discussed with Ville in the patch review move
the setting of the bifurcate bit into the ->crtc_enable hook. That way
we won't wreak havoc with this state when userspace puts all other
outputs into dpms off state. This also moves us forward with our
overall goal to unify the modeset and dpms on paths (which we need to
have to allow runtime pm in the dpms off state).

Unfortunately this requires us to move the bifurcate helpers around a
bit.

Also update the commit message, I've misanalyzed the bug rather badly.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70507Tested-by: Jan-Michael Brummer <jan.brummer@tabos.org>
Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

 * Add color overhead for stdio output buffer, which fixes
   --stdio output being chopped up on the hot (red) entries,
   fix from Jiri Olsa.

 * Get 'perf record -g -a sleep 1' working again, removing the
   need for -- separating perf options from the workload, restoring
   ages old behaviour, fix from Jiri Olsa.
   More patches allowing ~/.perfconfig setting up of default
   callchain collecting method ("fp" or "dwarf") left for next
   merge window.

 * Fixup mmap event consumption, where we were acking the
   consumption by writing the tail before actually accessing
   the event, which could lead to using overwritten records
   in things like 'perf record --call-graph'. From Zhouyi Zhou.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Pull Xtensa patchset from Chris Zankel:
 "The main patch fixes a bug that can cause a kernel panic, and was
  introduced in rc1.  The other two have been discovered by a uclibc
  test and 'coccinelle'"

* tag 'xtensa-next-20131015' of git://github.com/czankel/xtensa-linux:
  xtensa: Cocci spatch "noderef"
  xtensa: don't use alternate signal stack on threads
  xtensa: fix fast_syscall_spill_registers_fixup

Pull SCSI fixes from James Bottomley:
 "This is a set of four patches that revert functionality introduced in
  the merge window to sg.  The locking changes turned out to introduce
  this bug:

      [  205.372901] [ BUG: lock held when returning to user space! ]
   [...]
      [  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

  The fix is large, so at this late stage we'd like to revert the
  functionality and start again in the next merge window"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] Revert "sg: use rwsem to solve race during exclusive open"
  [SCSI] Revert "sg: no need sg_open_exclusive_lock"
  [SCSI] Revert "sg: checking sdp->detached isn't protected when open"
  [SCSI] Revert "sg: push file descriptor list locking down to per-device locking"

The tail position of the event buffer should only be modified after
actually use that event.

If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.
Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Splitting -G and --call-graph for record command, so we could use '-G'
with no option.

The '-G' option now takes NO argument and enables the configured unwind
method, which is currently the frame pointers method.

It will be possible to configure unwind method via config file in
upcoming patches.

All current '-G' arguments is overtaken by --call-graph option.

NOTE: The documentation for top --call-graph option
      was wrongly copied from report command.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: David Ahern <dsahern@gmail.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382797536-32303-3-git-send-email-jolsa@redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Splitting -g and --call-graph for record command, so we could use '-g'
with no option.

The '-g' option now takes NO argument and enables the configured unwind
method, which is currently the frame pointers method.

It will be possible to configure unwind method via config file in
upcoming patches.

All current '-g' arguments is overtaken by --call-graph option.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: David Ahern <dsahern@gmail.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382797536-32303-2-git-send-email-jolsa@redhat.com
[ reordered -g/--call-graph on --help and expanded the man page
  according to comments by David Ahern and Namhyung Kim ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Following commit tightened up the buffer size for output to strict width
of used format columns:

  99cf666c perf hists: Fix formatting of long symbol names

This works fine until you hit color overhead output which places extra
bytes into output buffer. We need to account for color overhead in the
output buffer. Adding maximum color byte size to the output buffer size.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382700293-1803-1-git-send-email-jolsa@redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The Intel D410PT(LW) and D425KT Mini-ITX desktop boards both show up as
having LVDS but the hardware is not populated. This patch adds them to
the list of such systems. Patch is against 3.11.4

v2: Patch revised to match the D425KT exactly as the D425KTW does have
LVDS.  According to Intel's documentation, the D410PTL and D410PLTW
don't.
Signed-off-by: Rob Pearce <rob@flitspace.org.uk>
Cc: stable@vger.kernel.org
[danvet: Pimp commit message to my liking and add cc: stable.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This isn't a real fix to the problem, but rather a stopgap measure while
trying to find a proper solution.

There are several laptops out there that fail to light up the eDP panel
in UEFI boot mode. They seem to be mostly IVB machines, including but
apparently not limited to Dell XPS 13, Asus TX300, Asus UX31A, Asus
UX32VD, Acer Aspire S7. They seem to work in CSM or legacy boot.

The difference between UEFI and CSM is that the BIOS provides a
different VBT to the kernel. The UEFI VBT typically specifies 18 bpp and
1.62 GHz link for eDP, while CSM VBT has 24 bpp and 2.7 GHz link. We end
up clamping to 18 bpp in UEFI mode, which we can fit in the 1.62 Ghz
link, and for reasons yet unknown fail to light up the panel.

Dithering from 24 to 18 bpp itself seems to work; if we use 18 bpp with
2.7 GHz link, the eDP panel lights up. So essentially this is a link
speed issue, and *not* a bpp clamping issue.

The bug raised its head since
commit 657445fe
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Sat May 4 10:09:18 2013 +0200

    Revert "drm/i915: revert eDP bpp clamping code changes"

which started clamping bpp *before* computing the link requirements, and
thus affecting the required bandwidth. Clamping after the computations
kept the link at 2.7 GHz.

Even though the BIOS tells us to use 18 bpp through the VBT, it happily
boots up at 24 bpp and 2.7 GHz itself! Use this information to
selectively ignore the VBT provided value.

We can't ignore the VBT eDP bpp altogether, as there are other laptops
that do require the clamping to be used due to EDID reporting higher bpp
than the panel can support.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=59841
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67950Tested-by: Ulf Winkelvos <ulf@winkelvos.de>
Tested-by: jkp <jkp@iki.fi>
CC: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Call intel_ddi_get_config() to get the pipe_bpp settings from
DDI.

The sync polarity settings from DDI are irrelevant for CRT
output, so override them with data from the ADPA register.

Note: This is already merged in drm-intel-next-queued as

commit 6801c18c
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Tue Sep 24 14:24:05 2013 +0300

    drm/i915: Add HSW CRT output readout support

but is required for the following edp bpp bugfix.

v2: Extract intel_crt_get_flags()

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69691Tested-by: Qingshuai Tian <qingshuai.tian@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

* Fix up /proc/PID/maps parsing, where perfectly fine mmap entries
  were being trown away when synthesizing PERF_RECORD_MMAP for
  preexisting threads, prevenging symbol resolution to work
  for those threads, broken in the MMAP2 removal. Reported and
  pinpointed by Markus Trippelsdorf,

* Fix mem leak in the python 'perf script' backend, due to missing Py_DECREFs
  on dict entries, fix from Joseph Schuchart.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

When introducing support for MMAP2 we considered more parts of each map
representation in /proc/PID/maps, and when disabling it we forgot to
reduce the number of expected parsed/assigned entries in the sscanf
call, fix it to expect the right number of desired fields, 5.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Based-on-a-patch-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-vrbo1wik997ahjzl1chm3bdm@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

On CTG+ read out the pipe bpp setting from hardware and fill it into
pipe config. Also check it appropriately.

v2: Don't do the pipe_bpp extraction inside the PCH only code block on
    ILK+.
    Avoid the PIPECONF read as we already have read it for the
    PIPECONF_EANBLE check.

Note: This is already in drm-intel-next-queued as
commit 42571aef
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Fri Sep 6 23:29:00 2013 +0300

    drm/i915: Add support for pipe_bpp readout

but is needed for the following bugfix.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Pull parisc fix from Helge Deller:
 "This is a 2-line patch to save the CPU register which holds our task
  thread info pointer before calling a firmware function and then to
  restore it again afterwards.

  This is necessary because on some 64bit machines the high-order 32bits
  are being clobbered by the firmware call, and thus we failed to bring
  up secondary CPUs (and instead crashed the kernel) in some situations
  eg if we had more than 4GB RAM.  This patch fixes a bug which has been
  since ever in the parisc linux kernel and which prevented some people
  to use a 64bit kernel"

* 'parisc-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Do not crash 64bit SMP kernels on machines with >= 4GB RAM

Pull timer fix from Ingo Molnar:
 "This tree contains a clockevents regression fix for certain ARM
  subarchitectures"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clockevents: Sanitize ticks to nsec conversion

Pull perf fixes from Ingo Molnar:
 "The tree contains three fixes:

   - Two tooling fixes

   - Reversal of the new 'MMAP2' extended mmap record ABI, introduced in
     this merge window.  (Patches were proposed to fix it but it was all
     a bit late and we felt it's safer to just delay the ABI one more
     kernel release and do it right)"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Disable PERF_RECORD_MMAP2 support
  perf scripting perl: Fix build error on Fedora 12
  perf probe: Fix to initialize fname always before use it

Pull locking fix from Ingo Molnar:
 "This tree fixes a boot crash in CONFIG_DEBUG_MUTEXES=y kernels, on
  kernels built with GCC 3.x (there are still such distros)"

Side note: it's not just a fix for old gcc versions, it's also removing
an incredibly broken/subtle check that LLVM had issues with, and that
made no sense.

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mutex: Avoid gcc version dependent __builtin_constant_p() usage

Pull SCSI target fixes from Nicholas Bellinger:
 "Here are the outstanding target pending fixes for v3.12-rc7.

  This includes a number of EXTENDED_COPY related fixes as a result of
  Thomas and Doug's continuing testing and feedback.

  Also included is an important vhost/scsi fix that addresses a long
  standing issue where the 'write' parameter for get_user_pages_fast()
  was incorrectly set for virtio-scsi WRITEs -> DMA_TO_DEVICE, and not
  for virtio-scsi READs -> DMA_FROM_DEVICE.

  This resulted in random userspace segfaults and other unpleasantness
  on KVM host, and unfortunately has been an issue since the initial
  merge of vhost/scsi in v3.6.  This patch is CC'ed to stable, along
  with two other less critical items"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter
  target/pscsi: fix return value check
  target: Fail XCOPY for non matching source + destination block_size
  target: Generate failure for XCOPY I/O with non-zero scsi_status
  target: Add missing XCOPY I/O operation sense_buffer
  iser-target: check device before dereferencing its variable
  target: Return an error for WRITE SAME with ANCHOR==1
  target: Fix assignment of LUN in tracepoints
  target: Reject EXTENDED_COPY when emulate_3pc is disabled
  target: Allow non zero ListID in EXTENDED_COPY parameter list
  target: Make target_do_xcopy failures return INVALID_PARAMETER_LIST

Pull slave-dmaengine fixes from Vinod Koul:
 "Here is the late fixes pull request for dmaengine while you fly back
  from KS.

  We have a new dmaengine ML hosted by vger so a patch for that along
  with addition of Dave as driver mainatainer for ioat.  Other fixes are
  memeory leak fixes on edma driver, small fixes on rcar-hpbdma driver
  by Sergei"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: edma: fix another memory leak
  dma: edma: Fix memory leak
  MAINTAINERS: add to ioatdma maintainer list
  MAINTAINERS: add the new dmaengine mailing list

Since the beginning of the parisc-linux port, sometimes 64bit SMP kernels were
not able to bring up other CPUs than the monarch CPU and instead crashed the
kernel.  The reason was unclear, esp. since it involved various machines (e.g.
J5600, J6750 and SuperDome). Testing showed, that those crashes didn't happened
when less than 4GB were installed, or if a 32bit Linux kernel was booted.

In the end, the fix for those SMP problems is trivial:
During the early phase of the initialization of the CPUs, including the monarch
CPU, the PDC_PSW firmware function to enable WIDE (=64bit) mode is called.
It's documented that this firmware function may clobber various registers, and
one one of those possibly clobbered registers is %cr30 which holds the task
thread info pointer.

Now, if %cr30 would always have been clobbered, then this bug would have been
detected much earlier. But lots of testing finally showed, that - at least for
%cr30 - on some machines only the upper 32bits of the 64bit register suddenly
turned zero after the firmware call.

So, after finding the root cause, the explanation for the various crashes
became clear:
- On 32bit SMP Linux kernels all upper 32bit were zero, so we didn't faced this
  problem.
- Monarch CPUs in 64bit mode always booted sucessfully, because the inital task
  thread info pointer was below 4GB.
- Secondary CPUs booted sucessfully on machines with less than 4GB RAM because
  the upper 32bit were zero anyay.
- Secondary CPus failed to boot if we had more than 4GB RAM and the task thread
  info pointer was located above the 4GB boundary.

Finally, the patch to fix this problem is trivial by saving the %cr30 register
before the firmware call and restoring it afterwards.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # 2.6.12+
Signed-off-by: Helge Deller <deller@gmx.de>