> -----Original Message----- > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > Sent: Thursday, November 19, 2015 6:29 PM > To: Nikula, Jani > Cc: Lu, Han; daniel.vetter@xxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; > libin.yang@xxxxxxxxxxxxxxx; mengdong.lin@xxxxxxxxxxxxxxx; > han.lu@xxxxxxxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/1] drm/i915/audio: apply SKL codec wake up patch to > BXT > > On Thu, 19 Nov 2015 10:09:01 +0100, > Jani Nikula wrote: > > > > On Thu, 19 Nov 2015, Jani Nikula <jani.nikula@xxxxxxxxx> wrote: > > > On Thu, 19 Nov 2015, han.lu@xxxxxxxxx wrote: > > >> From: "Lu, Han" <han.lu@xxxxxxxxx> > > >> > > >> Signed-off-by: Lu, Han <han.lu@xxxxxxxxx> > > >> > > >> diff --git a/drivers/gpu/drm/i915/intel_audio.c > > >> b/drivers/gpu/drm/i915/intel_audio.c > > >> index 63d4706..8310bf3 100644 > > >> --- a/drivers/gpu/drm/i915/intel_audio.c > > >> +++ b/drivers/gpu/drm/i915/intel_audio.c > > >> @@ -591,7 +591,8 @@ static void > i915_audio_component_codec_wake_override(struct device *dev, > > >> struct drm_i915_private *dev_priv = dev_to_i915(dev); > > >> u32 tmp; > > >> > > >> - if (!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv)) > > >> + if (!IS_SKYLAKE(dev_priv) && !IS_BROXTON(dev_priv) && > > >> + !IS_KABYLAKE(dev_priv)) > > > > > > How about if (INTEL_INFO(dev_priv)->gen < 9)? > > > > Oh, and I guess we also wonder why this is only relevant for the > > latest platforms? > > My understanding is that it's a workaround specific to HSW/BDW. > It's issued only during the audio controller initialization and at the resume. > But I never know why it's needed, it's a black magic :) > > > Takashi Sorry, I should have made it more clear. For SKL we added a patch (commit 632f3ab95fe2ffebf09969a57ab21), in order to enable codec wakeup override signal, to allow re-enumeration of the controller on SKL after resume from low power state. 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. Reset steps when power on: enable codec wakeup -> azx_init_chip() -> disable codec wakeup Since the power well design didn't change from SKL to BXT, we need to apply the workaround to BXT also. I'll re-submit the patch with these info added on. Regards, Han Lu _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
