On Fri, 11 Nov 2016, "Yang, Libin" <libin.yang@xxxxxxxxx> wrote: > Hi Jani, > >> -----Original Message----- >> From: Jani Nikula [mailto:jani.nikula@xxxxxxxxxxxxxxx] >> Sent: Thursday, November 10, 2016 6:37 PM >> To: Yang, Libin <libin.yang@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; >> ville.syrjala@xxxxxxxxxxxxxxx; Vetter, Daniel <daniel.vetter@xxxxxxxxx>; >> tiwai@xxxxxxx >> Cc: Yang, Libin <libin.yang@xxxxxxxxx> >> Subject: Re: [PATCH v2] drm/i915/audio: fix hdmi audio noise issue >> >> On Thu, 10 Nov 2016, libin.yang@xxxxxxxxx wrote: >> > From: Libin Yang <libin.yang@xxxxxxxxx> >> > >> > Some monitors will have noise or even no sound after applying the >> > patch 6014ac12. >> > >> > In patch 6014ac12, it will reset the cts value to 0 for HDMI. >> > However, we need to disable Enable CTS or M Prog bit. This is the >> > initial setting after HW reset. >> > >> > Fixes: 6014ac122ed0 ("drm/i915/audio: set proper N/M in modeset") >> > Signed-off-by: Libin Yang <libin.yang@xxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/intel_audio.c | 15 ++++++++++++--- >> > 1 file changed, 12 insertions(+), 3 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/intel_audio.c >> > b/drivers/gpu/drm/i915/intel_audio.c >> > index 813fd74..a472d35 100644 >> > --- a/drivers/gpu/drm/i915/intel_audio.c >> > +++ b/drivers/gpu/drm/i915/intel_audio.c >> > @@ -332,6 +332,13 @@ hsw_hdmi_audio_config_update(struct intel_crtc >> *intel_crtc, enum port port, >> > int n; >> > u32 tmp; >> > >> > + /* reset CTS value to 0 */ >> > + tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe)); >> > + tmp &= ~AUD_CONFIG_M_MASK; >> > + tmp &= ~AUD_M_CTS_M_VALUE_INDEX; >> > + tmp |= AUD_M_CTS_M_PROG_ENABLE; >> > + I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp); >> > + >> > tmp = I915_READ(HSW_AUD_CFG(pipe)); >> > tmp &= ~AUD_CONFIG_N_VALUE_INDEX; >> > tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK; >> > @@ -351,10 +358,12 @@ hsw_hdmi_audio_config_update(struct intel_crtc >> > *intel_crtc, enum port port, >> > >> > I915_WRITE(HSW_AUD_CFG(pipe), tmp); >> > >> > + /* >> > + * Let's disable "Enable CTS or M Prog bit" >> > + * and let HW calculate the value >> > + */ >> > tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe)); >> > - tmp &= ~AUD_CONFIG_M_MASK; >> > - tmp &= ~AUD_M_CTS_M_VALUE_INDEX; >> > - tmp |= AUD_M_CTS_M_PROG_ENABLE; >> > + tmp &= ~AUD_M_CTS_M_PROG_ENABLE; >> > I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp); >> >> You did not address my review comment on the earlier version: >> >> Is it necessary to do the HSW_AUD_M_CTS_ENABLE updates in two places? >> Why do you both enable and disable AUD_M_CTS_M_PROG_ENABLE bit here? > > Sorry, I missed your comments. > > The first doing the HSW_AUD_M_CTS_ENABLE is to reset the M value to 0. > The second doing the HSW_AUD_M_CTS_ENABLE is to let HW calculate the M value. > > Or we can just try to disable the HSW_AUD_M_CTS_ENABLE bit. What's your opinion? I would have thought just doing the latter would be sufficient. Please test. BR, Jani. > > Regards, > Libin > >> >> BR, >> Jani. >> >> >> > } >> >> -- >> Jani Nikula, Intel Open Source Technology Center -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
