linux/include
Takashi Iwai 664c715573 ALSA: hda - Work around races of power up/down with runtime PM
Currently, snd_hdac_power_up()/down() helpers checks whether the codec
is being in pm (suspend/resume), and skips the call of runtime get/put
during it.  This is needed as there are lots of power up/down
sequences called in the paths that are also used in the PM itself.  An
example is found in hda_codec.c::codec_exec_verb(), where this can
power up the codec while it may be called again in its power up
sequence, too.

The above works in most cases, but sometimes we really want to wait
for the real power up.  For example, the control element get/put may
want explicit power up so that the value change is assured to reach to
the hardware.   Using the current snd_hdac_power_up(), however,
results in a race, e.g. when it's called during the runtime suspend is
being performed.  In the worst case, as found in patch_ca0132.c, it
can even lead to the deadlock because the code assumes the power up
while it was skipped due to the check above.

For dealing with such cases, this patch makes snd_hdac_power_up() and
_down() to two variants: with and without in_pm flag check.  The
version with pm flag check is named as snd_hdac_power_up_pm() while
the version without pm flag check is still kept as
snd_hdac_power_up().  (Just because the usage of the former is fewer.)

Then finally, the patch replaces each call potentially done in PM with
the new _pm() variant.

In theory, we can implement a unified version -- if we can distinguish
the current context whether it's in the pm path.  But such an
implementation is cumbersome, so leave the code like this a bit messy
way for now...

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96271
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-04-08 13:50:42 +02:00
..
acpi Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2015-02-19 11:28:36 -08:00
asm-generic OK, this has the big virtio 1.0 implementation, as specified by OASIS. 2015-02-18 09:24:01 -08:00
clocksource
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2015-02-14 09:47:01 -08:00
drm drm/ttm: device address space != CPU address space 2015-03-05 09:04:39 +10:00
dt-bindings ARM: dts: am43xx: fix SLEWCTRL_FAST pinctrl binding 2015-03-06 09:21:03 -08:00
keys
kvm arm/arm64: KVM: Keep elrsr/aisr in sync with software model 2015-03-14 13:42:07 +01:00
linux mm: numa: slow PTE scan rate if migration failures occur 2015-03-25 16:20:31 -07:00
math-emu
media
memory
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2015-03-22 16:57:07 -04:00
pcmcia
ras
rdma Revert "IB/core: Add support for extended query device caps" 2015-02-06 00:54:33 -08:00
rxrpc
scsi Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block 2015-02-12 14:13:23 -08:00
soc pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories. 2015-03-03 19:43:59 +01:00
sound ALSA: hda - Work around races of power up/down with runtime PM 2015-04-08 13:50:42 +02:00
target target: do not reject FUA CDBs when write cache is enabled but emulate_write_cache is 0 2015-03-19 23:26:46 -07:00
trace regmap: introduce regmap_name to fix syscon regmap trace events 2015-03-19 20:04:55 +00:00
uapi Merge branch 'for-next' into topic/hda-core 2015-03-23 13:14:02 +01:00
video OMAPDSS: fix regression with display sysfs files 2015-02-26 10:23:15 +02:00
xen xen: Remove trailing semicolon from xenbus_register_frontend() definition 2015-03-02 10:38:59 +00:00
Kbuild