> -----Original Message----- > From: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > Sent: Wednesday, April 10, 2024 3:47 PM > To: Shankar, Uma <uma.shankar@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; > intel-xe@xxxxxxxxxxxxxxxxxxxxx > Cc: Borah, Chaitanya Kumar <chaitanya.kumar.borah@xxxxxxxxx>; Shankar, Uma > <uma.shankar@xxxxxxxxx> > Subject: Re: [PATCH] drm/i915: Implement Audio WA_14020863754 > > On Wed, 10 Apr 2024, Uma Shankar <uma.shankar@xxxxxxxxx> wrote: > > WA_14020863754: Corner case with Min Hblank Fix can cause audio hang > > > > Issue: Previously a fix was made to avoid issues with extremely small > > hblanks, called the "Min Hblank Fix". However, this can potentially > > cause an audio hang. > > > > Workaround : > > During "Audio Programming Sequence" Audio Enabling - When DP mode is > > enabled Set mmio offset 0x65F1C bit 18 = 1b, before step #1 "Enable > > audio Presence Detect" > > > > During "Audio Programming Sequence" Audio Disabling - When DP mode is > > enabled Clear mmio offset 0x65F1C bit 18 = 0b, after step #6 "Disable > > Audio PD (Presence Detect)" > > If not clearing PD bit, must also not clear 0x65F1C bit 18 (leave = > > 1b) > > hsw_audio_codec_disable/enable get called on hsw and display ver >= 8, but a lot > of those platforms have the bit reserved MBZ. I didn't go through all the platforms > in bspec, but enough to notice this needs some platform check. Yes Jani, realized it after sending. Will update and re-float. Thanks for spotting it. Regards, Uma Shankar > BR, > Jani. > > > > > Signed-off-by: Uma Shankar <uma.shankar@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/display/intel_audio.c | 12 ++++++++++++ > > drivers/gpu/drm/i915/display/intel_audio_regs.h | 3 +++ > > 2 files changed, 15 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_audio.c > > b/drivers/gpu/drm/i915/display/intel_audio.c > > index 07e0c73204f3..a8e3e515aaa0 100644 > > --- a/drivers/gpu/drm/i915/display/intel_audio.c > > +++ b/drivers/gpu/drm/i915/display/intel_audio.c > > @@ -512,6 +512,12 @@ static void hsw_audio_codec_disable(struct > intel_encoder *encoder, > > intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD, > > AUDIO_OUTPUT_ENABLE(cpu_transcoder), 0); > > > > + /* > > + * WA_14020863754: Implement Audio Workaround > > + * Corner case with Min Hblank Fix can cause audio hang > > + */ > > + intel_de_rmw(i915, AUD_CHICKENBIT_REG3, CHICKEN3_SPARE18, 0); > > + > > mutex_unlock(&i915->display.audio.mutex); > > } > > > > @@ -637,6 +643,12 @@ static void hsw_audio_codec_enable(struct > intel_encoder *encoder, > > if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP)) > > enable_audio_dsc_wa(encoder, crtc_state); > > > > + /* > > + * WA_14020863754: Implement Audio Workaround > > + * Corner case with Min Hblank Fix can cause audio hang > > + */ > > + intel_de_rmw(i915, AUD_CHICKENBIT_REG3, 0, CHICKEN3_SPARE18); > > + > > /* Enable audio presence detect */ > > intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD, > > 0, AUDIO_OUTPUT_ENABLE(cpu_transcoder)); > > diff --git a/drivers/gpu/drm/i915/display/intel_audio_regs.h > > b/drivers/gpu/drm/i915/display/intel_audio_regs.h > > index 616e7b1275c4..6f8d33299ecd 100644 > > --- a/drivers/gpu/drm/i915/display/intel_audio_regs.h > > +++ b/drivers/gpu/drm/i915/display/intel_audio_regs.h > > @@ -148,4 +148,7 @@ > > #define HBLANK_START_COUNT_96 4 > > #define HBLANK_START_COUNT_128 5 > > > > +#define AUD_CHICKENBIT_REG3 _MMIO(0x65F1C) > > +#define CHICKEN3_SPARE18 REG_BIT(18) > > + > > #endif /* __INTEL_AUDIO_REGS_H__ */ > > -- > Jani Nikula, Intel
