On Tue, Apr 28, 2015 at 05:21:30PM +0300, Jani Nikula wrote: > On Tue, 28 Apr 2015, han.lu@xxxxxxxxx wrote: > > From: "Lu, Han" <han.lu@xxxxxxxxx> > > > > In SKL, HDMI/DP codec and PCH HD Audio Controller are in different > > power wells, so it's necessary to reset display audio codecs when > > power well on, otherwise display audio codecs will disappear when > > resume from low power state. > > The reset step when power on is: > > enable codec wakeup -> azx_init_chip() -> disable codec wakeup > > > > The callback is defined in drivers/gpu/drm/i915/. > > The caller is in sound/pci/hda/. > > Han Lu, two more things: > > First, is there any chance the chicken bit register is mirrored in the > audio device mmio bar? If yes, you could use it directly in the audio > driver, and we could drop patch 1/2... > > Second, looking at the audio driver code for the usage of this callback > in patch 2/2, I don't think the locking and refcounting add any > value. Especially since you ignore the refcounting for disable. You're > the only user, and anything beyond that would be broken anyway, with or > without refcounting or locking. In fact, I'd like to push back the > locking and refcounting to audio driver side, where you may realize they > are not needed at all. Thus, I propose this as patch 1/2: > > From b06bf55b94cdbfad8ec35923b2b657674472cce5 Mon Sep 17 00:00:00 2001 > From: "Lu, Han" <han.lu@xxxxxxxxx> > Date: Tue, 28 Apr 2015 17:03:08 +0300 > Subject: [PATCH] drm/i915/audio: add codec wakeup override enabled/disable > callback > Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> > > Add support for enabling codec wakeup override signal to allow > re-enumeration of the controller on SKL after resume from low power > state. This commit message is missing the explanation and specifically the hw sequence. Lu's original patch has a nice paragraph explaining all that. With that re-added this is Acked-by: me for merging through the sound tree (which seems to be the best option here I think). -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
