linux-kernel - Re: [PATCH] Wait for all codecs to be ready if doing a cold reset

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Date:	Mon, 07 Jul 2008 18:39:09 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Thadeu Lima de Souza Cascardo <cascardo@...aslivre.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Wait for all codecs to be ready if doing a cold reset

At Sun, 6 Jul 2008 14:15:56 -0300,
Thadeu Lima de Souza Cascardo wrote:
> 
> If AC97_POWER_SAVE is enabled, intel8x0 does a cold reset when
> initializing the codecs. While resuming, it does not wait for all codecs
> to be active. Sound card does not work after a resume without it,
> however. This patch fixes it.

Thanks for the patch.

But, I still don't figure out why this is needed.
In the else block (with the comment "resume phase"), you can find the
loop to wait for the all *probed* codecs.  The difference with the
code you moved is that it checks only the bits corresponding to the
already probed codecs.  In other words, the other bits should be
irrelevant with the hardware.

I guess it's not about the loop but the additional 1/4 sec delay that
did fix the resume on your device.  Please check how is the status
bits and whether it passed the loop in the middle.


Takashi


> ---
>  sound/pci/intel8x0.c |   24 ++++++++++++++----------
>  1 files changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
> index 048d99e..7228a0a 100644
> --- a/sound/pci/intel8x0.c
> +++ b/sound/pci/intel8x0.c
> @@ -2335,16 +2335,6 @@ static int snd_intel8x0_ich_chip_init(struct intel8x0 *chip, int probing)
>  				   igetdword(chip, ICHREG(GLOB_STA)));
>  			return -EIO;
>  		}
> -
> -		/* wait for other codecs ready status. */
> -		end_time = jiffies + HZ / 4;
> -		while (status != chip->codec_isr_bits &&
> -		       time_after_eq(end_time, jiffies)) {
> -			schedule_timeout_uninterruptible(1);
> -			status |= igetdword(chip, ICHREG(GLOB_STA)) &
> -				chip->codec_isr_bits;
> -		}
> -
>  	} else {
>  		/* resume phase */
>  		int i;
> @@ -2363,6 +2353,20 @@ static int snd_intel8x0_ich_chip_init(struct intel8x0 *chip, int probing)
>  		} while (time_after_eq(end_time, jiffies));
>  	}
>  
> +#ifndef CONFIG_SND_AC97_POWER_SAVE
> +	if (probing)
> +#endif
> +	{
> +		/* wait for other codecs ready status. */
> +		end_time = jiffies + HZ / 4;
> +		while (status != chip->codec_isr_bits &&
> +		       time_after_eq(end_time, jiffies)) {
> +			schedule_timeout_uninterruptible(1);
> +			status |= igetdword(chip, ICHREG(GLOB_STA)) &
> +				chip->codec_isr_bits;
> +		}
> +	}
> +
>  	if (chip->device_type == DEVICE_SIS) {
>  		/* unmute the output on SIS7012 */
>  		iputword(chip, 0x4c, igetword(chip, 0x4c) | 1);
> -- 
> 1.5.6
> 
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