Merging the HD-audio fixes back to base devel branch for further
working on it.

The commit [63e51fd7: ALSA: hda - Don't take unresponsive D3
transition too serious] introduced a conditional fallback behavior to
the HD-audio controller depending on the flag set.  However, it
introduced a silly bug, too, that the flag was evaluated in a reverse
way.  This resulted in a regression of HD-audio controller driver
where it can't go to the fallback mode at communication errors.

Unfortunately (or fortunately?) this didn't come up until recently
because the affected code path is an error handling that happens only
on an unstable hardware chip.  Most of recent chips work stably, thus
they didn't hit this problem.  Now, we've got a regression report with
a VIA chip, and this seems indeed requiring the fallback to the
polling mode, and finally the bug was revealed.

The fix is a oneliner to remove the wrong logical NOT in the check.
(Lesson learned - be careful about double negation.)

The bug should be backported to stable, but the patch won't be
applicable to 3.13 or earlier because of the code splits.  The stable
fix patches for earlier kernels will be posted later manually.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94021
Fixes: 63e51fd7 ('ALSA: hda - Don't take unresponsive D3 transition too serious')
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Takashi Iwai <tiwai@suse.de>

POLL_OUT isn't what callers of ->poll() are expecting to see; it's
actually __SI_POLL | 2 and it's a siginfo code, not a poll bitmap
bit...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Cc: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull USB fixes from Greg KH:
 "Here's a round of USB fixes for 4.0-rc3.

  Nothing major, the usual gadget, xhci and usb-serial fixes and a few
  new device ids as well.

  All have been in linux-next successfully"

* tag 'usb-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (36 commits)
  xhci: Workaround for PME stuck issues in Intel xhci
  xhci: fix reporting of 0-sized URBs in control endpoint
  usb: ftdi_sio: Add jtag quirk support for Cyber Cortex AV boards
  USB: ch341: set tty baud speed according to tty struct
  USB: serial: cp210x: Adding Seletek device id's
  USB: pl2303: disable break on shutdown
  USB: mxuport: fix null deref when used as a console
  USB: serial: clean up bus probe error handling
  USB: serial: fix port attribute-creation race
  USB: serial: fix tty-device error handling at probe
  USB: serial: fix potential use-after-free after failed probe
  USB: console: add dummy __module_get
  USB: ftdi_sio: add PIDs for Actisense USB devices
  Revert "USB: serial: make bulk_out_size a lower limit"
  cdc-acm: Add support for Denso cradle CU-321
  usb-storage: support for more than 8 LUNs
  uas: Add US_FL_NO_REPORT_OPCODES for JMicron JMS539
  USB: usbfs: don't leak kernel data in siginfo
  xhci: Clear the host side toggle manually when endpoint is 'soft reset'
  xhci: Allocate correct amount of scratchpad buffers
  ...

Pull tty/serial fixes from Greg KH:
 "Here are some tty and serial driver fixes for 4.0-rc3.

  Along with the atime fix that you know about, here are some other
  serial driver bugfixes as well.  Most notable is a wait_until_sent
  bugfix that was traced back to being around since before 2.6.12 that
  Johan has fixed up.

  All have been in linux-next successfully"

* tag 'tty-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  TTY: fix tty_wait_until_sent maximum timeout
  TTY: fix tty_wait_until_sent on 64-bit machines
  USB: serial: fix infinite wait_until_sent timeout
  TTY: bfin_jtag_comm: remove incorrect wait_until_sent operation
  net: irda: fix wait_until_sent poll timeout
  serial: uapi: Declare all userspace-visible io types
  serial: core: Fix iotype userspace breakage
  serial: sprd: Fix missing spin_unlock in sprd_handle_irq()
  console: Fix console name size mismatch
  tty: fix up atime/mtime mess, take four
  serial: 8250_dw: Fix get_mctrl behaviour
  serial:8250:8250_pci: delete unneeded quirk entries
  serial:8250:8250_pci: fix redundant entry report for WCH_CH352_2S
  Change email address for 8250_pci
  serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO"
  Revert "tty/serial: of_serial: add DT alias ID handling"

Pull staging driver fixes from Greg KH:
 "Here are some IIO and staging driver fixes for 4.0-rc3.

  Details are in the shortlog, nothing major, mostly IIO fixes for
  reported issues.

  All have been in linux-next successfully"

* tag 'staging-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (23 commits)
  staging: comedi: adv_pci1710: fix AI INSN_READ for non-zero channel
  staging: comedi: vmk80xx: remove "firmware version" kernel messages
  staging: comedi: comedi_isadma: fix "stalled" detect in comedi_isadma_disable_on_sample()
  iio: ak8975: fix AK09911 dependencies
  iio: common: ssp_sensors: Protect PM-only functions to kill warning
  IIO: si7020: Allocate correct amount of memory in devm_iio_device_alloc
  Revert "iio:humidity:si7020: fix pointer to i2c client"
  iio: light: gp2ap020a00f: Select REGMAP_I2C
  iio: light: jsa1212: Select REGMAP_I2C
  iio: ad5686: fix optional reference voltage declaration
  iio:adc:mcp3422 Fix incorrect scales table
  iio: mxs-lradc: fix iio channel map regression
  iio: imu: adis16400: Fix sign extension
  staging: iio: ad2s1200: Fix sign extension
  iio: mxs-lradc: only update the buffer when its conversions have finished
  iio: mxs-lradc: make ADC reads not unschedule touchscreen conversions
  iio: mxs-lradc: make ADC reads not disable touchscreen interrupts
  iio: mxs-lradc: separate touchscreen and buffer virtual channels
  iio: imu: inv_mpu6050: Prevent dereferencing NULL
  iio: iadc: wait_for_completion_timeout time in jiffies
  ...

Pull char/misc driver fixes from Greg KH:
 "Here are two char/misc fixes for 4.0-rc3.

  One is a reported binder driver fix needed due to a change in the mm
  core that happened in 4.0-rc1.  Another is a mei driver fix that
  resolves a reported issue in that driver.

  Both have been in linux-next for a while"

* tag 'char-misc-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  mei: make device disabled on stop unconditionally
  android: binder: fix binder mmap failures

Pull "code of conflict" from Greg KH:
 "This file tries to set the rational basis for our code reviews, gives
  some advice on how to conduct them, and provides an excalation channel
  for any kernel developers if they so desire it"

[ Let's see how this works ]

* tag 'cc-4.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Code of Conflict

Pull i2c fixes from Wolfram Sang:
 "A set of updates and bugfixes for the new designware-baytrail driver.

  And a documentation bugfix"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: imx: add required clocks property to binding
  i2c: designware-baytrail: baytrail_i2c_acquire() might sleep
  i2c: designware-baytrail: cross-check lock functions
  i2c: designware-baytrail: fix sparse warnings
  i2c: designware-baytrail: fix typo in error path
  i2c: designware-baytrail: describe magic numbers

Pull slave-dmaengine fixes from Vinod Koul:
 "This contains small fixes spread across the drivers"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: mmp_pdma: fix warning about slave caps
  dmaengine: qcom_bam_dma: fix wrong register offsets
  dmaengine: bam-dma: fix a warning about missing capabilities
  dmaengine: ioatdma: workaround for incorrect DMACAP register
  dmaengine: at_xdmac: fix for chan conf simplification
  dmaengine: dw: don't handle interrupt when dmaengine is not used
  dma: mmp-tdma: refine dma disable and dma-pos update
  dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks
  dmaenegine: mmp-pdma: fix irq handler overwrite physical chan issue

Pull arm64 fixes from Catalin Marinas:
 "arm64 and generic kernel/module.c (acked by Rusty) fixes for
  CONFIG_DEBUG_SET_MODULE_RONX"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kernel/module.c: Update debug alignment after symtable generation
  arm64: Don't use is_module_addr in setting page attributes

Currently tty_wait_until_sent may take up to twice as long as the
requested timeout while waiting for driver and hardware buffers to
drain.

Fix this by taking the remaining number of jiffies after waiting for
driver buffers to drain into account so that the timeout actually
becomes a maximum timeout as it is documented to be.

Note that this specifically implies tighter timings when closing a port
as a consequence of actually honouring the port closing-wait setting
for drivers relying on tty_wait_until_sent_from_close (e.g. via
tty_port_close_start).
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an
infinite timeout (0) would be passed to the underlying tty-driver's
wait_until_sent-operation as a negative timeout (-1), causing it to
return immediately.

This manifests itself for example as tcdrain() returning immediately,
drivers not honouring the drain flags when setting terminal attributes,
or even dropped data on close as a requested infinite closing-wait
timeout would be ignored.

The first symptom  was reported by Asier LLANO who noted that tcdrain()
returned prematurely when using the ftdi_sio usb-serial driver.

Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the
underlying tty driver.

Note that the serial-core wait_until_sent-implementation is not affected
by this bug due to a lucky chance (comparison to an unsigned maximum
timeout), and neither is the cyclades one that had an explicit check for
negative timeouts, but all other tty drivers appear to be affected.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>	# v2.6.12
Reported-by: ZIV-Asier Llano Palacios <asier.llano@cgglobal.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure to handle an infinite timeout (0).

Note that wait_until_sent is currently never called with a 0-timeout
argument due to a bug in tty_wait_until_sent.

Fixes: dcf01050 ("USB: serial: add generic wait_until_sent
implementation")
Cc: stable <stable@vger.kernel.org>	# v3.10
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove incorrect and redundant wait_until_sent operation, which waits
for the driver buffer rather than any hardware buffers to drain,
something which is already taken care of by the tty layer (and
chars_in_buffer).
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In case an infinite timeout (0) is requested, the irda wait_until_sent
implementation would use a zero poll timeout rather than the default
200ms.

Note that wait_until_sent is currently never called with a 0-timeout
argument due to a bug in tty_wait_until_sent.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>	# v2.6.12
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ioctl(TIOCGSERIAL|TIOCSSERIAL) report and can change the port->iotype.
UART drivers use the UPIO_* definitions, but the uapi header defines
parallel values and userspace uses these parallel values for ioctls;
thus the userspace values are definitive.

Define UPIO_* iotypes in terms of the uapi defines, SERIAL_IO_*;
extend the uapi defines to include all values in use by the serial
core.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 3ffb1a81 ("serial: core: Add big-endian iotype")
re-numbered userspace-dependent values; ioctl(TIOCSSERIAL) can
assign the port iotype (which is expected to match the selected
i/o accessors), so iotype values must not be changed.

Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix return from sprd_handle_irq() with spin_lock held.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 6ae9200f ("enlarge console.name") increased the storage
for the console name to 16 bytes, but not the corresponding
struct console_cmdline::name storage. Console names longer than
8 bytes cause read beyond end-of-string and failure to match
console; I'm not sure if there are other unexpected consequences.

Cc: <stable@vger.kernel.org> # 2.6.22+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This problem was taken care of three times already in
* b0de59b5 (TTY: do not update
  atime/mtime on read/write),
* 37b7f3c7 (TTY: fix atime/mtime
  regression), and
* b0b88565 (tty: fix up atime/mtime
  mess, take three)

But it still misses one point. As John Paul correctly points out, we
do not care about setting date. If somebody ever changes wall
time backwards (by mistake for example), tty timestamps are never
updated until the original wall time passes.

So check the absolute difference of times and if it large than "8
seconds or so", always update the time. That means we will update
immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the
check, but it was always that way.

Thanks John for serving me this so nicely debugged.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: John Paul Perry <john_paul.perry@alcatel-lucent.com>
Cc: <stable@vger.kernel.org> # all, as b0b88565 was backported
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixed behaviour of get_mctrl() serial driver function as documented in:
https://www.kernel.org/doc/Documentation/serial/driver

Added device-tree properties 'dcd-override', 'dsr-override',
'cts-override', and 'ri-override' specific to the Synopsis 8250
DesignWare UART driver. Allows one to force Data Carrier Detect,
Clear To Send, and Data Set Ready signals to permanently be reported as
active. The Ring indicator can be forced to be reported as inactive.

It is possible that if modem control signalling is enabled on a port
that doesn't have these pins (e.g. - a simple two wire Tx/Rx port), the
driver can hang indefinitely waiting for the state to change. The new
DT properties allow the driver to ignore the state of these pins on
serial ports that don't support them, as recommended in the kernel
documentation.
Reviewed-by: JD (Jiandong) Zheng <jdzheng@broadcom.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

These quirk entries have the same effect as default
quirk entry, so we can just delete them.
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 8b5c913f
("serial: 8250_pci: Add WCH CH352 quirk to avoid Xscale detection")
trigger one redundant entry report message.

This patch fix it.
Reported-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

I'm still receiving reports to my email address, so let's point this
at the linux-serial mailing list instead.

Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 0aa525d1.

The conditional RX-FIFO read seems to cause spurious interrupts and we
see just:
|serial8250: too much work for irq29

The previous behaviour was "default" for decades and Marvell's 88f6282 SoC
might not be the only that relies on it. Therefore the Omap fix is
reverted for now.

Fixes: 0aa525d1 ("tty: serial: 8250_core: read only RX if there is
something in the FIFO")
Reported-By: Nicolas Schichan <nschichan@freebox.fr>
Debuged-By: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 6d01bb9d.

The exact same code was added in commit 3239fd31 (serial: of-serial: fetch
line number from DT) a few lined above. Doing this once should be enough.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull drm fixes from Dave Airlie:
 "Radeon, imx, msm, and i915 fixes.

  The msm, imx and i915 ones are fairly run of the mill.

  Radeon had some DP audio and posting reads for irq fixes, along with a
  fix for 32-bit kernels with new cards, we were using unsigned long to
  represent GPU side memory space, but since that changed size on 32 vs
  64 cards with lots of VRAM failed, so the change has no effect on
  x86-64, just moves to using uint64_t instead"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (35 commits)
  drm/msm: kexec fixes
  drm/msm/mdp5: fix cursor blending
  drm/msm/mdp5: fix cursor ROI
  drm/msm/atomic: Don't leak atomic commit object when commit fails
  drm/msm/mdp5: Avoid flushing registers when CRTC is disabled
  drm/msm: update generated headers (add 6th lm.base entry)
  drm/msm/mdp5: fixup "drm/msm: fix fallout of atomic dpms changes"
  drm/ttm: device address space != CPU address space
  drm/mm: Support 4 GiB and larger ranges
  drm/i915: gen4: work around hang during hibernation
  drm/i915: Check for driver readyness before handling an underrun interrupt
  drm/radeon: fix interlaced modes on DCE8
  drm/radeon: fix DRM_IOCTL_RADEON_CS oops
  drm/radeon: do a posting read in cik_set_irq
  drm/radeon: do a posting read in si_set_irq
  drm/radeon: do a posting read in evergreen_set_irq
  drm/radeon: do a posting read in r600_set_irq
  drm/radeon: do a posting read in rs600_set_irq
  drm/radeon: do a posting read in r100_set_irq
  radeon/audio: fix DP audio on DCE6
  ...

A clock specifier is required for i.MX I2C and is
provided in all DTS implementations. Add this to the
list of required properties in the binding.
Signed-off-by: Matt Porter <mporter@konsulko.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

This patch marks baytrail_i2c_acquire() that it might sleep. Also it chages
while-loop to do-while and, though it is matter of taste, gives a chance to
check one more time before report a timeout.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

It seems the idea behind the cross-check is to prevent acquire semaphore when
there is no release callback and vice versa. Thus, patch fixes a typo.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

There is no need to export functions that are used as the callbacks in the
struct dw_i2c_dev. Otherwise we get the following warnings:

drivers/i2c/busses/i2c-designware-baytrail.c:63:5: warning: symbol 'baytrail_i2c_acquire' was not declared. Should it be static?
drivers/i2c/busses/i2c-designware-baytrail.c:114:6: warning: symbol 'baytrail_i2c_release' was not declared. Should it be static?

While here, do few indentation fixes, remove i2c_dw_eval_lock_support() from
functions exported to the modules and redundant assignment of local sem
variable.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

It seems we have same message for different return values in get_sem() and
baytrail_i2c_acquire(). I suspect this is just a typo, so this patch fixes it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

The patch converts hardcoded numerical constants to a named ones.

While here, align the variable name in get_sem() and reset_semaphore().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Pull btrfs fixes from Chris Mason:
 "Outside of misc fixes, Filipe has a few fsync corners and we're
  pulling in one more of Josef's fixes from production use here"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.
  Btrfs: fix data loss in the fast fsync path
  Btrfs: remove extra run_delayed_refs in update_cowonly_root
  Btrfs: incremental send, don't rename a directory too soon
  btrfs: fix lost return value due to variable shadowing
  Btrfs: do not ignore errors from btrfs_lookup_xattr in do_setxattr
  Btrfs: fix off-by-one logic error in btrfs_realloc_node
  Btrfs: add missing inode update when punching hole
  Btrfs: abort the transaction if we fail to update the free space cache inode
  Btrfs: fix fsync race leading to ordered extent memory leaks

Pull livepatching fix from Jiri Kosina:
 "Fix an RCU unlock misplacement in live patching infrastructure, from
  Peter Zijlstra"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: fix RCU usage in klp_find_external_symbol()

Pull thermal management fixes from Eduardo Valentin:
 "Specifics:

   - adding Lukasz as maintainer of samsung thermal driver.
   - driver fixes: exynos and int430x.
   - one fix in the exynos cpufreq driver related to cpu cooling (acked
     by cpufreq maintainer).
   - fix default sysfs attributes of cooling devices

  Note: I am sending this pull on Rui's behalf while he fixes issues in his Linux box"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
  thermal: Make sysfs attributes of cooling devices default attributes
  Thermal/int340x: Fix memleak for aux trip
  MAINTAINERS: Add entry for SAMSUNG THERMAL DRIVER
  cpufreq: exynos: Use simple approach to asses if cpu cooling can be used
  thermal: exynos: Fix wrong control of power down detection mode for Exynos7

two fixes, both cc'd stable.

* tag 'drm-intel-fixes-2015-03-05' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: gen4: work around hang during hibernation
  drm/i915: Check for driver readyness before handling an underrun interrupt

Linux 4.0-rc2

Merging this manually as the i915 change is in it,
and intel fixes are on top of this