Commit Graph

244398 Commits

Author SHA1 Message Date
Kuninori Morimoto b002ff6e26 usb: renesas_usbhs: add autonomy mode
Current renesas_usbhs was designed to save power when USB is not connected.
And it assumed platform uses callback to notify connection/disconnection
by external interrupt.

But some SuperH / platform board doesn't have such feature.

This patch adds autonomy mode which detect USB connection/disconnection
by internal interrupt.
But power will be always ON when autonomy mode is selected.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:35 -07:00
Kuninori Morimoto bc57381e63 usb: renesas_usbhs: use delayed_work instead of work_struct
This delay is used to overjump debounce.

And, this patch also move usbhsc_drvcllbck_notify_hotplug to global,
because it will be called from other files.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:34 -07:00
Kuninori Morimoto 5ea68d541d usb: renesas_usbhs: prevent NULL pointer crash
usbhs_status_get_each_irq/usbhs_irq_callback_update might be called
with mod == NULL

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:34 -07:00
Kuninori Morimoto 6e267da8f1 usb: renesas_usbhs: add power control function
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:34 -07:00
Kuninori Morimoto 206dcc2cfe usb: renesas_usbhs: move pdev_to_priv to global
usbhs_pdev_to_priv function will be used in other files.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:33 -07:00
Kuninori Morimoto f429ea3f34 usb: renesas_usbhs: add error reason for usbhs_pipe_malloc
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:33 -07:00
Kuninori Morimoto af32fe5113 usb: renesas_usbhs: remove callback when module removed.
The callback function which is called from platform must be removed
if module removed.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:32 -07:00
Kuninori Morimoto 9a28b7bd4f usb: renesas_usbhs: return error if wrong recip request
There are some USB Host which doesn't notice disconnection at once.
And it might try some request after reconnection with old settings.
Current renesas_usbhs will crash in such case.
This patch prevent this issue.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:32 -07:00
Kuninori Morimoto cb96632c18 usb: renesas_usbhs: modify spinlock method
Current renesas_usbhs driver was using spin_trylock to avoid
dead lock / nest lock.
But acording to CONFIG_DEBUG_SPINLOCK, it is BUG under UP environment.
This patch add usbhsg_trylock to avoid this issue.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:32 -07:00
Kuninori Morimoto 409ba9e7c0 usb: renesas_usbhs: don't re-allocation pipe buffer
Because pipe buffer allocation is very picky and difficult,
current renesas_usbhs driver is not caring pipe re-allocation.

In this situation, driver will create new pipe without caring old pipe
if "usbhsg_ep_enable" is called after "usbhsg_ep_disable" on current driver.
This mean the limited pipe and buffer will be used as waste.
But it is possible to re-use same buffer to same pipe.

By this patch, driver will initialize pipe when it detected new connection or
new gadget, and doesn't try re-allocation for same pipe in above case.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:31 -07:00
Kuninori Morimoto 45e13e6e0a usb: renesas_usbhs: modify fifo clear timing
Pipe buffer should be cleaned before using it,
but should NOT be cleaned in pipe "prepare" function.
Because the pipe might be working in such timing.
This patch fixup this issue.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:31 -07:00
Jonas Andersson a0c25c2050 USB: g_printer required set interface request
g_printer reqiured "set interface" request from host. Not all hosts send
this request.  This patch enable the interface when it get "set
configuration" request from host.

Signed-off-by: Jonas Andersson <jonas@microbit.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:31 -07:00
Sven Schnelle a8779ee94e USB: dbpg gadget: dont mask out direction bit
Stripping the direction bit off will produce an
invalid descriptor.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:30 -07:00
Sven Schnelle 83b7201993 USB: dbgp gadget: set MaxpacketSize0
The current code doesn't set it, so linux complains about
it when connected, and ignores the device:

[104611.068082] usb 1-5: new high speed USB device using ehci_hcd and address 127
[104611.088368] usb 1-5: Invalid ep0 maxpacket: 0

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:30 -07:00
Sven Schnelle 1744020ceb USB: dbgp gadget: fix return value of dbgp_setup
Current code returns 0 even if it can't handle the request.
This leads to timeouts when an unhandled request is sent:

Bus 001 Device 003: ID 0525:c0de Netchip Technology, Inc.
Device Descriptor:
[..]
can't get device qualifier: Connection timed out
[..]

change the code to return EOPNOTSUPP in such cases.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:30 -07:00
Kuninori Morimoto 25a73c6ce7 usb: renesas_usbhs: Driver is depend on SuperH
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:29 -07:00
Kuninori Morimoto c89d2613b8 usb: renesas_usbhs: fixup cast warning
This patch fixup cast warning on 64 bit compiler

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reported-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:29 -07:00
Alan Stern 6498d9db6d USB: documentation update for the pre_reset method
This patch (as1459) updates the documentation for the pre_reset method
in struct usb_driver.  When a driver is notified of an impending
reset, it must cancel all outstanding I/O and not start any new I/O
until it has been notified that the reset is complete.

As far as I know, most existing drivers that implement pre_reset do
this now.  The major exceptions appear to be the SpeedTouch and
CDC-WDM drivers.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:24:29 -07:00
Marius B. Kotsbak 15b2f3204a Bind only modem AT command endpoint to option module.
Network interface is handled by upcoming gt_b3730 module.

Removed "GT-B3710" from comment, it is another modem with another USB ID.

Signed-off-by: Marius B. Kotsbak <marius@kotsbak.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:05:06 -07:00
Oliver Neukum d771d8aa37 USB: cdc-wdm: reset handling according to new requirements
This patch
- ensures no IO takes place during resets
- reports resets to user space

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:04:40 -07:00
Hermann Kneissel b4026c4584 USB: gamin_gps: Fix for data transfer problems in native mode
This patch fixes a problem where data received from the gps is sometimes
transferred incompletely to the serial port. If used in native mode now
all data received via the bulk queue will be forwarded to the serial
port.

Signed-off-by: Hermann Kneissel <herkne@gmx.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 17:03:59 -07:00
Michal Nazarewicz 7701846fd5 USB: gadget: g_multi: fixed vendor and product ID in inf files
Commit 1c6529e92b "USB: gadget: g_multi: fixed vendor and
product ID" replaced g_multi's vendor and product ID with
proper ID's from Linux Foundation.  This commit now updates
INF files in the Documentation/usb directory which were
omitted in the original commit.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 16:45:22 -07:00
Benedek László 37909fe588 USB: serial: ftdi_sio: adding support for TavIR STK500
Adding support for the TavIR STK500 (id 0403:FA33)
Atmel AVR programmer device based on FTDI FT232RL.

Signed-off-by: Benedek László <benedekl@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 16:45:22 -07:00
Elizabeth Jennifer Myers 3938a0b32d USB: moto_modem: Add USB identifier for the Motorola VE240.
Tested on my phone, the ttyUSB device is created and is fully
functional.

Signed-off-by: Elizabeth Jennifer Myers <elizabeth@sporksirc.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 16:45:21 -07:00
Craig Shelley 4eff0b40a7 USB: CP210x Add 4 Device IDs for AC-Services Devices
This patch adds 4 device IDs for CP2102 based devices manufactured by
AC-Services. See http://www.ac-services.eu for further info.

Signed-off-by: Craig Shelley <craig@microtron.org.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-29 16:45:20 -07:00
Greg Kroah-Hartman 50ee9339c7 Merge 2.6.39-rc4 into usb-next
This is needed to help resolve some xhci issues and other minor
differences.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 05:50:38 -07:00
Linus Torvalds f0e615c3cb Linux 2.6.39-rc4 2011-04-18 21:26:00 -07:00
Linus Torvalds e024f69de9 Merge branch 'for-39-rc4' of git://codeaurora.org/quic/kernel/davidb/linux-msm
* 'for-39-rc4' of git://codeaurora.org/quic/kernel/davidb/linux-msm:
  msm: timer: fix missing return value
  msm: Remove extraneous ffa device check
2011-04-18 15:44:29 -07:00
Linus Torvalds 96fd2d57b8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: xen-kbdfront - fix mouse getting stuck after save/restore
  Input: estimate number of events per packet
  Input: evdev - indicate buffer overrun with SYN_DROPPED
  Input: document event types and codes and their intended use
  Input: add KEY_IMAGES specifically for AL Image Browser
  Input: twl4030_keypad - fix potential NULL dereference in twl4030_kp_probe()
  Input: h3600_ts - fix error handling at connect
  Input: twl4030_keypad - avoid potential NULL-pointer dereference
2011-04-18 13:29:03 -07:00
Linus Torvalds 8a83f33100 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: add blk_run_queue_async
  block: blk_delay_queue() should use kblockd workqueue
  md: fix up raid1/raid10 unplugging.
  md: incorporate new plugging into raid5.
  md: provide generic support for handling unplug callbacks.
  md - remove old plugging code.
  md/dm - remove remains of plug_fn callback.
  md: use new plugging interface for RAID IO.
  block: drop queue lock before calling __blk_run_queue() for kblockd punt
  Revert "block: add callback function for unplug notification"
  block: Enhance new plugging support to support general callbacks
2011-04-18 13:21:18 -07:00
Linus Torvalds 5d5b1b9f79 Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/powermac: Build fix with SMP and CPU hotplug
  powerpc/perf_event: Skip updating kernel counters if register value shrinks
  powerpc: Don't write protect kernel text with CONFIG_DYNAMIC_FTRACE enabled
  powerpc: Fix oops if scan_dispatch_log is called too early
  powerpc/pseries: Use a kmem cache for DTL buffers
  powerpc/kexec: Fix regression causing compile failure on UP
  powerpc/85xx: disable Suspend support if SMP enabled
  powerpc/e500mc: Remove CPU_FTR_MAYBE_CAN_NAP/CPU_FTR_MAYBE_CAN_DOZE
  powerpc/book3e: Fix CPU feature handling on 64-bit e5500
  powerpc: Check device status before adding serial device
  powerpc/85xx: Don't add disabled PCIe devices
2011-04-18 12:24:24 -07:00
Linus Torvalds adff377bb1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (24 commits)
  Btrfs: fix free space cache leak
  Btrfs: avoid taking the chunk_mutex in do_chunk_alloc
  Btrfs end_bio_extent_readpage should look for locked bits
  Btrfs: don't force chunk allocation in find_free_extent
  Btrfs: Check validity before setting an acl
  Btrfs: Fix incorrect inode nlink in btrfs_link()
  Btrfs: Check if btrfs_next_leaf() returns error in btrfs_real_readdir()
  Btrfs: Check if btrfs_next_leaf() returns error in btrfs_listxattr()
  Btrfs: make uncache_state unconditional
  btrfs: using cached extent_state in set/unlock combinations
  Btrfs: avoid taking the trans_mutex in btrfs_end_transaction
  Btrfs: fix subvolume mount by name problem when default mount subvolume is set
  fix user annotation in ioctl.c
  Btrfs: check for duplicate iov_base's when doing dio reads
  btrfs: properly handle overlapping areas in memmove_extent_buffer
  Btrfs: fix memory leaks in btrfs_new_inode()
  Btrfs: check for duplicate iov_base's when doing dio reads
  Btrfs: reuse the extent_map we found when calling btrfs_get_extent
  Btrfs: do not use async submit for small DIO io's
  Btrfs: don't split dio bios if we don't have to
  ...
2011-04-18 12:24:05 -07:00
Linus Torvalds d8bdc59f21 proc: do proper range check on readdir offset
Rather than pass in some random truncated offset to the pid-related
functions, check that the offset is in range up-front.

This is just cleanup, the previous commit fixed the real problem.

Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18 10:36:54 -07:00
Linus Torvalds c78193e9c7 next_pidmap: fix overflow condition
next_pidmap() just quietly accepted whatever 'last' pid that was passed
in, which is not all that safe when one of the users is /proc.

Admittedly the proc code should do some sanity checking on the range
(and that will be the next commit), but that doesn't mean that the
helper functions should just do that pidmap pointer arithmetic without
checking the range of its arguments.

So clamp 'last' to PID_MAX_LIMIT.  The fact that we then do "last+1"
doesn't really matter, the for-loop does check against the end of the
pidmap array properly (it's only the actual pointer arithmetic overflow
case we need to worry about, and going one bit beyond isn't going to
overflow).

[ Use PID_MAX_LIMIT rather than pid_max as per Eric Biederman ]

Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com>
Analyzed-by: Robert Święcki <robert@swiecki.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18 10:35:30 -07:00
Igor Mammedov c36b58e8a9 Input: xen-kbdfront - fix mouse getting stuck after save/restore
Mouse gets "stuck" after restore of PV guest but buttons are in working
condition.

If driver has been configured for ABS coordinates at start it will get
XENKBD_TYPE_POS events and then suddenly after restore it'll start getting
XENKBD_TYPE_MOTION events, that will be dropped later and they won't get
into user-space.

Regression was introduced by hunk 5 and 6 of
5ea5254aa0ad269cfbd2875c973ef25ab5b5e9db
("Input: xen-kbdfront - advertise either absolute or relative
coordinates").

Driver on restore should ask xen for request-abs-pointer again if it is
available. So restore parts that did it before 5ea5254.

Acked-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
[v1: Expanded the commit description]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-04-18 10:17:45 -07:00
Jeff Brown 80b4895aa4 Input: estimate number of events per packet
Calculate a default based on the number of ABS axes, REL axes,
and MT slots for the device during input device registration.

Signed-off-by: Jeff Brown <jeffbrown@android.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-04-18 10:15:43 -07:00
Chris Mason f65647c29b Btrfs: fix free space cache leak
The free space caching code was recently reworked to
cache all the pages it needed instead of using find_get_page everywhere.

One loop was missed though, so it ended up leaking pages.  This fixes
it to use our page array instead of find_get_page.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-18 08:55:34 -04:00
Christoph Hellwig 24ecfbe27f block: add blk_run_queue_async
Instead of overloading __blk_run_queue to force an offload to kblockd
add a new blk_run_queue_async helper to do it explicitly.  I've kept
the blk_queue_stopped check for now, but I suspect it's not needed
as the check we do when the workqueue items runs should be enough.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 11:41:33 +02:00
Jens Axboe 4521cc4ed5 block: blk_delay_queue() should use kblockd workqueue
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 11:36:39 +02:00
NeilBrown c3b328ac84 md: fix up raid1/raid10 unplugging.
We just need to make sure that an unplug event wakes up the md
thread, which is exactly what mddev_check_plugged does.

Also remove some plug-related code that is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:43 +10:00
NeilBrown 7c13edc875 md: incorporate new plugging into raid5.
In raid5 plugging is used for 2 things:
 1/ collecting writes that require a bitmap update
 2/ collecting writes in the hope that we can create full
    stripes - or at least more-full.

We now release these different sets of stripes when plug_cnt
is zero.

Also in make_request, we call mddev_check_plug to hopefully increase
plug_cnt, and wake up the thread at the end if plugging wasn't
achieved for some reason.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:43 +10:00
NeilBrown 97658cdd3a md: provide generic support for handling unplug callbacks.
When an md device adds a request to a queue, it can call
mddev_check_plugged.
If this succeeds then we know that the md thread will be woken up
shortly, and ->plug_cnt will be non-zero until then, so some
processing can be delayed.

If it fails, then no unplug callback is expected and the make_request
function needs to do whatever is required to make the request happen.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:42 +10:00
NeilBrown 482c083492 md - remove old plugging code.
md has some plugging infrastructure for RAID5 to use because the
normal plugging infrastructure required a 'request_queue', and when
called from dm, RAID5 doesn't have one of those available.

This relied on the ->unplug_fn callback which doesn't exist any more.

So remove all of that code, both in md and raid5.  Subsequent patches
with restore the plugging functionality.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:42 +10:00
NeilBrown af1db72d8b md/dm - remove remains of plug_fn callback.
Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:41 +10:00
NeilBrown e1dfa0a297 md: use new plugging interface for RAID IO.
md/raid submits a lot of IO from the various raid threads.
So adding start/finish plug calls to those so that some
plugging happens.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:41 +10:00
Jens Axboe 99e22598e9 block: drop queue lock before calling __blk_run_queue() for kblockd punt
If we know we are going to punt to kblockd, we can drop the queue
lock before calling into __blk_run_queue() since it only does a
safe bit test and a workqueue call. Since kblockd needs to grab
this very lock as one of the first things it does, it's a good
optimization to drop the lock before waking kblockd.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 09:59:55 +02:00
Jens Axboe b4cb290e0a Revert "block: add callback function for unplug notification"
MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.

This reverts commit f75664570d.

Conflicts:

	block/blk-core.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 09:54:05 +02:00
NeilBrown 048c9374a7 block: Enhance new plugging support to support general callbacks
md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.

So allow arbitrary callbacks to be attached to the blk_plug.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 09:52:22 +02:00
Benjamin Herrenschmidt 7b84b29b8c powerpc/powermac: Build fix with SMP and CPU hotplug
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-18 15:46:35 +10:00
Eric B Munson 86c74ab317 powerpc/perf_event: Skip updating kernel counters if register value shrinks
Because of speculative event roll back, it is possible for some event coutners
to decrease between reads on POWER7.  This causes a problem with the way that
counters are updated.  Delta calues are calculated in a 64 bit value and the
top 32 bits are masked.  If the register value has decreased, this leaves us
with a very large positive value added to the kernel counters.  This patch
protects against this by skipping the update if the delta would be negative.
This can lead to a lack of precision in the coutner values, but from my testing
the value is typcially fewer than 10 samples at a time.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: stable@kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-18 13:08:23 +10:00