ALSA: hda - Add power-welll support for haswell HDA
authorWang Xingchao <xingchao.wang@linux.intel.com>
Thu, 30 May 2013 14:07:10 +0000 (22:07 +0800)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Thu, 6 Jun 2013 15:31:56 +0000 (17:31 +0200)
commit99a2008d0b32d72dfc2a54e7be1eb698dd2e3bd6
treea4966a9b0e4c03e329875c17e998959e8a394e1b
parent5c90680e42b08a1e4a6800ca02e75ad201f8037f
ALSA: hda - Add power-welll support for haswell HDA

For Intel Haswell chip, HDA controller and codec have
power well dependency from GPU side. This patch added support
to request/release power well in audio driver. Power save
feature should be enabled to get runtime power saving.

There's deadlock when request_module(i915) in azx_probe.
It looks like:
device_lock(audio pci device) -> azx_probe -> module_request
(or symbol_request) -> modprobe (userspace) -> i915 init ->
drm_pci_init -> pci_register_driver -> bus_add_driver -> driver_attach ->
which in turn tries all locks on pci bus, and when it tries the one on the
audio device, it will deadlock.

This patch introduce a work to store remaining probe stuff, and let
request_module run in safe work context.

Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
sound/pci/hda/Kconfig
sound/pci/hda/Makefile
sound/pci/hda/hda_i915.c [new file with mode: 0644]
sound/pci/hda/hda_i915.h [new file with mode: 0644]
sound/pci/hda/hda_intel.c