linux-kernel - Re: [PATCH] ASoC: tlv320aic31xx: Add HP output driver pop reduction controls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ecfa48d3-284b-5234-02b9-adc0c6892b6f@cogentembedded.com>
Date:   Thu, 28 Nov 2019 15:19:38 +0300
From:   Nikita Yushchenko <nikita.yoush@...entembedded.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        "Andrew F. Davis" <afd@...com>,
        Guennadi Liakhovetski <guennadi.liakhovetski@...ux.intel.com>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        Chris Healy <cphealy@...il.com>
Subject: Re: [PATCH] ASoC: tlv320aic31xx: Add HP output driver pop reduction
 controls

>> +static const char * const hp_poweron_time_text[] = {
>> +	"0us", "15.3us", "153us", "1.53ms", "15.3ms", "76.2ms",
>> +	"153ms", "304ms", "610ms", "1.22s", "3.04s", "6.1s" };
>> +
>> +static SOC_ENUM_SINGLE_DECL(hp_poweron_time_enum, AIC31XX_HPPOP, 3,
>> +	hp_poweron_time_text);
>> +
>> +static const char * const hp_rampup_step_text[] = {
>> +	"0ms", "0.98ms", "1.95ms", "3.9ms" };
>> +
>> +static SOC_ENUM_SINGLE_DECL(hp_rampup_step_enum, AIC31XX_HPPOP, 1,
>> +	hp_rampup_step_text);
> 
> I'm not seeing any integration with DAPM here, I'd expect to see that so
> we don't cut off the start of audio especially with the longer times
> available (which I'm frankly not sure are seriously usable).

I believe driver already has that integration, there is aic31xx_dapm_power_event() that is called on 
DAPM events, and polls state in register bits waiting for operation to complete.

Btw, the default setting for register fields in question is "304ms" / "3.9ms" thus some delay is already 
there. This patch just makes it explicitly controllable by those who wait it.