linux-kernel - Re: [alsa-devel] [PATCH 9/9] ALSA: intel_hdmi: remove redundant variable cfg

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Date:   Mon, 6 Aug 2018 13:37:53 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     alsa-devel@...a-project.org,
        Olivier Moysan <olivier.moysan@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        kernel-janitors@...r.kernel.org,
        Arnaud Pouliquen <arnaud.pouliquen@...com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Colin King <colin.king@...onical.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Jaya Kumar <jayakumar.alsa@...il.com>
Subject: Re: [alsa-devel] [PATCH 9/9] ALSA: intel_hdmi: remove redundant
 variable cfg_val

On 8/1/18 6:00 AM, Takashi Iwai wrote:
> On Wed, 01 Aug 2018 12:47:42 +0200,
> Colin King wrote:
>>
>> From: Colin Ian King <colin.king@...onical.com>
>>
>> Variable cfg_val is being assigned but is never used hence it is
>> redundant and can be removed.
>>
>> Cleans up clang warning:
>> warning: variable 'cfg_val' set but not used [-Wunused-but-set-variable]
>>
>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
>> ---
>>   sound/x86/intel_hdmi_audio.c | 2 --
>>   1 file changed, 2 deletions(-)
>>
>> diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c
>> index edc9f5a34eff..fa7dca5a68c8 100644
>> --- a/sound/x86/intel_hdmi_audio.c
>> +++ b/sound/x86/intel_hdmi_audio.c
>> @@ -290,7 +290,6 @@ static void had_reset_audio(struct snd_intelhad *intelhaddata)
>>   static int had_prog_status_reg(struct snd_pcm_substream *substream,
>>   			struct snd_intelhad *intelhaddata)
>>   {
>> -	union aud_cfg cfg_val = {.regval = 0};
>>   	union aud_ch_status_0 ch_stat0 = {.regval = 0};
>>   	union aud_ch_status_1 ch_stat1 = {.regval = 0};
>>   
>> @@ -298,7 +297,6 @@ static int had_prog_status_reg(struct snd_pcm_substream *substream,
>>   					  IEC958_AES0_NONAUDIO) >> 1;
>>   	ch_stat0.regx.clk_acc = (intelhaddata->aes_bits &
>>   					  IEC958_AES3_CON_CLOCK) >> 4;
>> -	cfg_val.regx.val_bit = ch_stat0.regx.lpcm_id;
> 
> Actually this made me wonder what is the definition of val_bit.
> It seems always 1 in the current code after the commit 964ca8083c02.
> Pierre?

This val_bit is only there for debug/test, it should be set to one by 
default and has nothing to do with the lpcm_id. This variable was set 
even in patches before upstream submission and was never needed, I guess 
it must be a 9-yr old issue. Good catch!

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>

BTW looking at the structures in intel_hdmi_lpe_audio.h, the field 
format:3 in audio_ch_status_0 is misleading at best, it should be the 
emphasis if I look at the SPDIF/AES docs. It's not used but I'll have to 
relook at all this when I find some time... We should really set the 
registers to mirror what the aes_bits are, not just the non_audio and 
clock accuracy fields.