On Tue, 31 Oct 2017, "Kumar, Abhay" <abhay.kumar@xxxxxxxxx> wrote: > On 10/30/2017 5:21 PM, Pandiyan, Dhinakaran wrote: >> On Sun, 2017-10-29 at 03:04 +0000, Kumar, Abhay wrote: >>> + Subhransu >>> >>> -----Original Message----- >>> From: Intel-gfx [mailto:intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Kumar, Abhay >>> Sent: Thursday, October 26, 2017 12:10 PM >>> To: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>; Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>; subransu.s.prusty@xxxxxxxxx >>> Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Nujella, Sathyanarayana <sathyanarayana.nujella@xxxxxxxxx> >>> Subject: Re: [PATCH] drm/i915: set minimum CD clock to twice the BCLK. >>> >>> >>> >>> On 10/26/2017 1:45 AM, Jani Nikula wrote: >>>> On Wed, 25 Oct 2017, Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> wrote: >>>>> On Wednesday, October 25, 2017 3:02:12 PM PDT abhay.kumar@xxxxxxxxx wrote: >>>>>> From: Abhay Kumar <abhay.kumar@xxxxxxxxx> >>>>>> >>>>>> In glk when device boots with only 1366x768 panel, HDA codec doesn't comeup. >>>>>> This result in no audio forever as cdclk is < 96Mhz. >>>> Forever... or until next modeset with audio enabled? >>> Soundcard probing/detection and creation happens only during bootup. So even though we do modeset later there is no soundcard driver to handle the event. >>>>>> This chagne will ensure CD clock to be twice of BCLK. >>>>>> >>>>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102937 >>>>>> Signed-off-by: Abhay Kumar <abhay.kumar@xxxxxxxxx> >>>>>> --- >>>>>> drivers/gpu/drm/i915/intel_cdclk.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/drivers/gpu/drm/i915/intel_cdclk.c >>>>>> b/drivers/gpu/drm/i915/intel_cdclk.c index >>>>>> e8884c2ade98..185a70f0921c >>>>>> 100644 >>>>>> --- a/drivers/gpu/drm/i915/intel_cdclk.c >>>>>> +++ b/drivers/gpu/drm/i915/intel_cdclk.c >>>>>> @@ -1920,7 +1920,7 @@ int intel_crtc_compute_min_cdclk(const struct >>>>>> intel_crtc_state *crtc_state) /* According to BSpec, "The CD clock >>>>>> frequency must be at least twice * the frequency of the Azalia >>>>>> BCLK." and BCLK is 96 MHz by default. */ >>>>>> - if (crtc_state->has_audio && INTEL_GEN(dev_priv) >= 9) >>>>>> + if (INTEL_GEN(dev_priv) >= 9) >>>>> Why should cdclk be increased when audio is not being enabled? >>>> Indeed. I can easily imagine a counter-bug reporting excessive cdclk >>>> when audio is not enabled. >>> During bootup time audio driver is trying to acquire HDA audio power well inside i915 and then it will send HDA verb commands. >>> since cdclk is lower than 96Mhz HDA will not comeup resulting in timeout. This was working fine before SKL/APL since there was no 2 PPC . >>> >>> Is it ok to bump up cdclk while bootup of system/HDA and then reduce to needed CDCLK? >> I think it is worth exploring, do you have code to test whether it >> solves this particular issue? > No i don't have test code for this but what i learned from other OS that > glk run at 148000 and cnl 96000*2 due to this limitation all the time. Is there an HSD for this? It's a bit surprising you can't even probe the driver without a higher cdclk. BR, Jani. > > @Shubhransu : can you please answer this doubt which we all have. This > we should be able to get from HDA specs. > >> >>> wondering if this approach can cause any issue to subsequent HDA verb commands .. >>> >>> >>>> BR, >>>> Jani. >>>> >>>>>> min_cdclk = max(2 * 96000, min_cdclk); >>>>>> >>>>>> if (min_cdclk > dev_priv->max_cdclk_freq) { >>>>> _______________________________________________ >>>>> Intel-gfx mailing list >>>>> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >>>>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx >>> _______________________________________________ >>> Intel-gfx mailing list >>> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx > -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
