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

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Message-ID: <20080708165931.GA2882@vespa.holoscopio.com>
Date:	Tue, 8 Jul 2008 13:59:31 -0300
From:	Thadeu Lima de Souza Cascardo <cascardo@...aslivre.org>
To:	Takashi Iwai <tiwai@...e.de>
Subject: Re: [PATCH] Wait for all codecs to be ready if doing a cold reset

On Tue, Jul 08, 2008 at 12:16:35PM +0200, Takashi Iwai wrote:
> At Mon, 7 Jul 2008 14:36:55 -0300,
> Thadeu Lima de Souza Cascardo wrote:
> > 
> > On Mon, Jul 07, 2008 at 06:39:09PM +0200, Takashi Iwai wrote:
> > > 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
> > > 
> > > 
> > 
> > The 1/4 sec delay came in my mind as one of the possible reasons, and
> > that's why I've made some tests. status and nstatus are 0x200, while
> > codec_isr_bits is 0x300. The loop waits for the status register give us
> > 0x300 as the active codecs, instead of the only one probed. Since the
> > cold reset in the case of a power saving cleans up all codec registers,
> > it is needed that we wait for all codecs again (like in the probe case).
> 
> You loaded the modem driver as well?
> If so, what happens if you unload modem driver?
> 
> 
> thanks,
> 
> Takashi
> 

The modem driver has always been loaded. Unloading it with my patch
works OK.

> 
> > If you need more information or that I ran any more tests, I'd be glad
> > to do it. By the way, I've tested the patch against your audio and modem
> > merged version and it works OK.
> >
> > Best Regards,
> > Thadeu Cascardo.
> > 
> > > > ---
> > > >  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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