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2013-06-06ALSA: hda - Add power-welll support for haswell HDAWang Xingchao
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>