Re: [PATCH 2/3] ALSA: core: modify .ack callback to take arguments for updating appl ptr

["Subhransu S. Prusty" <subhransu.s.prusty@intel.com>]

On Tue, May 16, 2017 at 01:06:57PM +0530, Subhransu S. Prusty wrote:
> On Tue, May 16, 2017 at 07:56:44AM +0200, Takashi Iwai wrote:
> > On Tue, 16 May 2017 03:01:57 +0200,
> > Subhransu S. Prusty wrote:
> > > 
> > > From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > > 
> > > When appl_ptr is updated let low-level driver know, e.g.  to let the
> > > low-level driver/hardware pre-fetch data opportunistically.
> > > 
> > > The existing .ack callback is extended with new attribute argument, to
> > > support this capability. Legacy driver subscribe to SND_PCM_ACK_LEGACY and
> > > doesn't process ack if it is not set. SND_PCM_ACK_APP_PTR can be used to
> > > process the application ptr update in the driver like in the skylake
> > > driver which can use this to inform position of appl pointer to host DMA
> > > controller. The skylake driver to process the SND_PCM_ACK_APP_PTR will be
> > > submitted with a separate patch set.
> > > 
> > > In the ALSA core, this capability is independent from the NO_REWIND
> > > hardware flag. The low-level driver may however tie both options and only
> > > use the updated appl_ptr when rewinds are disabled due to hardware
> > > limitations.
> > > 
> > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > > Signed-off-by: Jaikrishna Nemallapudi <jaikrishnax.nemallapudi@intel.com>
> > > Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
> > 
> > It might be me who suggested the extension of the ack ops, but now
> > looking at the result, I reconsider whether it'd be a better choice if
> > we add another ops (e.g. update_appl_ptr()) instead.  Could you try to
> > rewrite the patch in that way for comparison?
> 
> Here is the version using update_appl_ptr.

Hi Takashi,

Did you get a chance to look at the update_appl_ptr changes?
Please let us know which one will be preferable, will submit the patches
accordingly.

Regards,
Subhransu

> 
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index 5344c16854d3..1accb8b522d3 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -87,6 +87,7 @@ struct snd_pcm_ops {
>  			     unsigned long offset);
>  	int (*mmap)(struct snd_pcm_substream *substream, struct vm_area_struct *vma);
>  	int (*ack)(struct snd_pcm_substream *substream);
> +	int (*appl_ptr_update)(struct snd_pcm_substream *substream);
>  };
>  
>  /*
> diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
> index bb1261591a1f..1656ca903c08 100644
> --- a/sound/core/pcm_lib.c
> +++ b/sound/core/pcm_lib.c
> @@ -2090,6 +2090,9 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
>  		if (substream->ops->ack)
>  			substream->ops->ack(substream);
>  
> +		if (substream->ops->appl_ptr_update)
> +			substream->ops->appl_ptr_update(substream);
> +
>  		offset += frames;
>  		size -= frames;
>  		xfer += frames;
> @@ -2322,6 +2325,9 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
>  		if (substream->ops->ack)
>  			substream->ops->ack(substream);
>  
> +		if (substream->ops->appl_ptr_update)
> +			substream->ops->appl_ptr_update(substream);
> +
>  		offset += frames;
>  		size -= frames;
>  		xfer += frames;
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index be8617be12e9..c56d4ed17497 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -2475,6 +2475,10 @@ static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *subst
>  		appl_ptr += runtime->boundary;
>  	runtime->control->appl_ptr = appl_ptr;
>  	ret = frames;
> +
> +	if (substream->ops->appl_ptr_update)
> +		substream->ops->appl_ptr_update(substream);
> +
>   __end:
>  	snd_pcm_stream_unlock_irq(substream);
>  	return ret;
> @@ -2526,6 +2530,10 @@ static snd_pcm_sframes_t snd_pcm_capture_rewind(struct snd_pcm_substream *substr
>  		appl_ptr += runtime->boundary;
>  	runtime->control->appl_ptr = appl_ptr;
>  	ret = frames;
> +
> +	if (substream->ops->appl_ptr_update)
> +		substream->ops->appl_ptr_update(substream);
> +
>   __end:
>  	snd_pcm_stream_unlock_irq(substream);
>  	return ret;
> @@ -2575,6 +2583,10 @@ static snd_pcm_sframes_t snd_pcm_playback_forward(struct snd_pcm_substream *subs
>  		appl_ptr -= runtime->boundary;
>  	runtime->control->appl_ptr = appl_ptr;
>  	ret = frames;
> +
> +	if (substream->ops->appl_ptr_update)
> +		substream->ops->appl_ptr_update(substream);
> +
>   __end:
>  	snd_pcm_stream_unlock_irq(substream);
>  	return ret;
> @@ -2624,6 +2636,10 @@ static snd_pcm_sframes_t snd_pcm_capture_forward(struct snd_pcm_substream *subst
>  		appl_ptr -= runtime->boundary;
>  	runtime->control->appl_ptr = appl_ptr;
>  	ret = frames;
> +
> +	if (substream->ops->appl_ptr_update)
> +		substream->ops->appl_ptr_update(substream);
> +
>   __end:
>  	snd_pcm_stream_unlock_irq(substream);
>  	return ret;
> @@ -2723,8 +2739,14 @@ static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
>  			return err;
>  	}
>  	snd_pcm_stream_lock_irq(substream);
> -	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL))
> +	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
> +		/* boundary wrap-around is assumed to be handled in userspace */
>  		control->appl_ptr = sync_ptr.c.control.appl_ptr;
> +
> +		/* let low-level driver know about appl_ptr change */
> +		if (substream->ops->appl_ptr_update)
> +			substream->ops->appl_ptr_update(substream);
> +	}
>  	else
>  		sync_ptr.c.control.appl_ptr = control->appl_ptr;
>  	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
> 
> 
> Regards,
> Subhransu
> > 
> > Besides that, the flag name SND_PCM_ACK_LEGACY sounds too ambiguous to
> > me...
> > 
> > 
> > thanks,
> > 
> > Takashi
> > 
> > > ---
> > >  include/sound/pcm-indirect.h  |  4 ++--
> > >  include/sound/pcm.h           |  8 +++++++-
> > >  sound/core/pcm_lib.c          |  6 ++++--
> > >  sound/core/pcm_native.c       | 24 +++++++++++++++++++++++-
> > >  sound/mips/hal2.c             | 14 +++++++++++---
> > >  sound/pci/cs46xx/cs46xx_lib.c | 18 ++++++++++++++----
> > >  sound/pci/emu10k1/emupcm.c    |  8 ++++++--
> > >  sound/pci/rme32.c             | 15 ++++++++++++---
> > >  8 files changed, 79 insertions(+), 18 deletions(-)
> > > 
> > > diff --git a/include/sound/pcm-indirect.h b/include/sound/pcm-indirect.h
> > > index 1df7acaaa535..2f647ff970fb 100644
> > > --- a/include/sound/pcm-indirect.h
> > > +++ b/include/sound/pcm-indirect.h
> > > @@ -101,7 +101,7 @@ typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream,
> > >  	if (rec->sw_io >= rec->sw_buffer_size)
> > >  		rec->sw_io -= rec->sw_buffer_size;
> > >  	if (substream->ops->ack)
> > > -		substream->ops->ack(substream);
> > > +		substream->ops->ack(substream, SND_PCM_ACK_LEGACY);
> > >  	return bytes_to_frames(substream->runtime, rec->sw_io);
> > >  }
> > >  
> > > @@ -170,7 +170,7 @@ typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream,
> > >  	if (rec->sw_io >= rec->sw_buffer_size)
> > >  		rec->sw_io -= rec->sw_buffer_size;
> > >  	if (substream->ops->ack)
> > > -		substream->ops->ack(substream);
> > > +		substream->ops->ack(substream, SND_PCM_ACK_LEGACY);
> > >  	return bytes_to_frames(substream->runtime, rec->sw_io);
> > >  }
> > >  
> > > diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> > > index a2682c5f5b72..0151552342f9 100644
> > > --- a/include/sound/pcm.h
> > > +++ b/include/sound/pcm.h
> > > @@ -63,6 +63,12 @@ struct snd_pcm_hardware {
> > >  struct snd_pcm_audio_tstamp_config; /* definitions further down */
> > >  struct snd_pcm_audio_tstamp_report;
> > >  
> > > +/*
> > > + * Attibute to distinguish the ack for legacy code and pointer update.
> > > + */
> > > +#define SND_PCM_ACK_LEGACY		BIT(0) /* Legacy callback */
> > > +#define SND_PCM_ACK_APP_PTR		BIT(1) /* Update pointer callback */
> > > +
> > >  struct snd_pcm_ops {
> > >  	int (*open)(struct snd_pcm_substream *substream);
> > >  	int (*close)(struct snd_pcm_substream *substream);
> > > @@ -86,7 +92,7 @@ struct snd_pcm_ops {
> > >  	struct page *(*page)(struct snd_pcm_substream *substream,
> > >  			     unsigned long offset);
> > >  	int (*mmap)(struct snd_pcm_substream *substream, struct vm_area_struct *vma);
> > > -	int (*ack)(struct snd_pcm_substream *substream);
> > > +	int (*ack)(struct snd_pcm_substream *substream, unsigned int ack_attr);
> > >  };
> > >  
> > >  /*
> > > diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
> > > index 5088d4b8db22..b25af69a67da 100644
> > > --- a/sound/core/pcm_lib.c
> > > +++ b/sound/core/pcm_lib.c
> > > @@ -2089,7 +2089,8 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
> > >  			appl_ptr -= runtime->boundary;
> > >  		runtime->control->appl_ptr = appl_ptr;
> > >  		if (substream->ops->ack)
> > > -			substream->ops->ack(substream);
> > > +			substream->ops->ack(substream, SND_PCM_ACK_LEGACY |
> > > +						SND_PCM_ACK_APP_PTR);
> > >  
> > >  		offset += frames;
> > >  		size -= frames;
> > > @@ -2321,7 +2322,8 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
> > >  			appl_ptr -= runtime->boundary;
> > >  		runtime->control->appl_ptr = appl_ptr;
> > >  		if (substream->ops->ack)
> > > -			substream->ops->ack(substream);
> > > +			substream->ops->ack(substream, SND_PCM_ACK_LEGACY |
> > > +						SND_PCM_ACK_APP_PTR);
> > >  
> > >  		offset += frames;
> > >  		size -= frames;
> > > diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> > > index 35dd4ca93f84..c14cdbd9ff86 100644
> > > --- a/sound/core/pcm_native.c
> > > +++ b/sound/core/pcm_native.c
> > > @@ -2476,6 +2476,10 @@ static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *subst
> > >  		appl_ptr += runtime->boundary;
> > >  	runtime->control->appl_ptr = appl_ptr;
> > >  	ret = frames;
> > > +
> > > +	if (substream->ops->ack)
> > > +		substream->ops->ack(substream, SND_PCM_ACK_APP_PTR);
> > > +
> > >   __end:
> > >  	snd_pcm_stream_unlock_irq(substream);
> > >  	return ret;
> > > @@ -2527,6 +2531,10 @@ static snd_pcm_sframes_t snd_pcm_capture_rewind(struct snd_pcm_substream *substr
> > >  		appl_ptr += runtime->boundary;
> > >  	runtime->control->appl_ptr = appl_ptr;
> > >  	ret = frames;
> > > +
> > > +	if (substream->ops->ack)
> > > +		substream->ops->ack(substream, SND_PCM_ACK_APP_PTR);
> > > +
> > >   __end:
> > >  	snd_pcm_stream_unlock_irq(substream);
> > >  	return ret;
> > > @@ -2576,6 +2584,10 @@ static snd_pcm_sframes_t snd_pcm_playback_forward(struct snd_pcm_substream *subs
> > >  		appl_ptr -= runtime->boundary;
> > >  	runtime->control->appl_ptr = appl_ptr;
> > >  	ret = frames;
> > > +
> > > +	if (substream->ops->ack)
> > > +		substream->ops->ack(substream, SND_PCM_ACK_APP_PTR);
> > > +
> > >   __end:
> > >  	snd_pcm_stream_unlock_irq(substream);
> > >  	return ret;
> > > @@ -2625,6 +2637,10 @@ static snd_pcm_sframes_t snd_pcm_capture_forward(struct snd_pcm_substream *subst
> > >  		appl_ptr -= runtime->boundary;
> > >  	runtime->control->appl_ptr = appl_ptr;
> > >  	ret = frames;
> > > +
> > > +	if (substream->ops->ack)
> > > +		substream->ops->ack(substream, SND_PCM_ACK_APP_PTR);
> > > +
> > >   __end:
> > >  	snd_pcm_stream_unlock_irq(substream);
> > >  	return ret;
> > > @@ -2726,8 +2742,14 @@ static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
> > >  			return err;
> > >  	}
> > >  	snd_pcm_stream_lock_irq(substream);
> > > -	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL))
> > > +	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
> > > +		/* boundary wrap-around is assumed to be handled in userspace */
> > >  		control->appl_ptr = sync_ptr.c.control.appl_ptr;
> > > +
> > > +		/* let low-level driver know about appl_ptr change */
> > > +		if (substream->ops->ack)
> > > +			substream->ops->ack(substream, SND_PCM_ACK_APP_PTR);
> > > +	}
> > >  	else
> > >  		sync_ptr.c.control.appl_ptr = control->appl_ptr;
> > >  	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
> > > diff --git a/sound/mips/hal2.c b/sound/mips/hal2.c
> > > index 00fc9241d266..3740381b188a 100644
> > > --- a/sound/mips/hal2.c
> > > +++ b/sound/mips/hal2.c
> > > @@ -577,7 +577,7 @@ static int hal2_playback_trigger(struct snd_pcm_substream *substream, int cmd)
> > >  	case SNDRV_PCM_TRIGGER_START:
> > >  		hal2->dac.pcm_indirect.hw_io = hal2->dac.buffer_dma;
> > >  		hal2->dac.pcm_indirect.hw_data = 0;
> > > -		substream->ops->ack(substream);
> > > +		substream->ops->ack(substream, SND_PCM_ACK_LEGACY);
> > >  		hal2_start_dac(hal2);
> > >  		break;
> > >  	case SNDRV_PCM_TRIGGER_STOP:
> > > @@ -610,11 +610,15 @@ static void hal2_playback_transfer(struct snd_pcm_substream *substream,
> > >  
> > >  }
> > >  
> > > -static int hal2_playback_ack(struct snd_pcm_substream *substream)
> > > +static int hal2_playback_ack(struct snd_pcm_substream *substream,
> > > +			     unsigned int ack_attr)
> > >  {
> > >  	struct snd_hal2 *hal2 = snd_pcm_substream_chip(substream);
> > >  	struct hal2_codec *dac = &hal2->dac;
> > >  
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	dac->pcm_indirect.hw_queue_size = H2_BUF_SIZE / 2;
> > >  	snd_pcm_indirect_playback_transfer(substream,
> > >  					   &dac->pcm_indirect,
> > > @@ -702,11 +706,15 @@ static void hal2_capture_transfer(struct snd_pcm_substream *substream,
> > >  	memcpy(substream->runtime->dma_area + rec->sw_data, buf, bytes);
> > >  }
> > >  
> > > -static int hal2_capture_ack(struct snd_pcm_substream *substream)
> > > +static int hal2_capture_ack(struct snd_pcm_substream *substream,
> > > +			    unsigned int ack_attr)
> > >  {
> > >  	struct snd_hal2 *hal2 = snd_pcm_substream_chip(substream);
> > >  	struct hal2_codec *adc = &hal2->adc;
> > >  
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	snd_pcm_indirect_capture_transfer(substream,
> > >  					  &adc->pcm_indirect,
> > >  					  hal2_capture_transfer);
> > > diff --git a/sound/pci/cs46xx/cs46xx_lib.c b/sound/pci/cs46xx/cs46xx_lib.c
> > > index e4cf3187b4dd..877edda61e45 100644
> > > --- a/sound/pci/cs46xx/cs46xx_lib.c
> > > +++ b/sound/pci/cs46xx/cs46xx_lib.c
> > > @@ -883,10 +883,15 @@ static void snd_cs46xx_pb_trans_copy(struct snd_pcm_substream *substream,
> > >  	memcpy(cpcm->hw_buf.area + rec->hw_data, runtime->dma_area + rec->sw_data, bytes);
> > >  }
> > >  
> > > -static int snd_cs46xx_playback_transfer(struct snd_pcm_substream *substream)
> > > +static int snd_cs46xx_playback_transfer(struct snd_pcm_substream *substream,
> > > +					unsigned int ack_attr)
> > >  {
> > >  	struct snd_pcm_runtime *runtime = substream->runtime;
> > >  	struct snd_cs46xx_pcm * cpcm = runtime->private_data;
> > > +
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	snd_pcm_indirect_playback_transfer(substream, &cpcm->pcm_rec, snd_cs46xx_pb_trans_copy);
> > >  	return 0;
> > >  }
> > > @@ -900,9 +905,14 @@ static void snd_cs46xx_cp_trans_copy(struct snd_pcm_substream *substream,
> > >  	       chip->capt.hw_buf.area + rec->hw_data, bytes);
> > >  }
> > >  
> > > -static int snd_cs46xx_capture_transfer(struct snd_pcm_substream *substream)
> > > +static int snd_cs46xx_capture_transfer(struct snd_pcm_substream *substream,
> > > +					       unsigned int ack_attr)
> > >  {
> > >  	struct snd_cs46xx *chip = snd_pcm_substream_chip(substream);
> > > +
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	snd_pcm_indirect_capture_transfer(substream, &chip->capt.pcm_rec, snd_cs46xx_cp_trans_copy);
> > >  	return 0;
> > >  }
> > > @@ -981,11 +991,11 @@ static int snd_cs46xx_playback_trigger(struct snd_pcm_substream *substream,
> > >  			cs46xx_dsp_pcm_link(chip,cpcm->pcm_channel);
> > >  
> > >  		if (substream->runtime->periods != CS46XX_FRAGS)
> > > -			snd_cs46xx_playback_transfer(substream);
> > > +			snd_cs46xx_playback_transfer(substream, SND_PCM_ACK_LEGACY);
> > >  #else
> > >  		spin_lock(&chip->reg_lock);
> > >  		if (substream->runtime->periods != CS46XX_FRAGS)
> > > -			snd_cs46xx_playback_transfer(substream);
> > > +			snd_cs46xx_playback_transfer(substream, SND_PCM_ACK_LEGACY);
> > >  		{ unsigned int tmp;
> > >  		tmp = snd_cs46xx_peek(chip, BA1_PCTL);
> > >  		tmp &= 0x0000ffff;
> > > diff --git a/sound/pci/emu10k1/emupcm.c b/sound/pci/emu10k1/emupcm.c
> > > index ef1cf530c929..74c78df6e5a8 100644
> > > --- a/sound/pci/emu10k1/emupcm.c
> > > +++ b/sound/pci/emu10k1/emupcm.c
> > > @@ -1627,11 +1627,15 @@ static void fx8010_pb_trans_copy(struct snd_pcm_substream *substream,
> > >  	pcm->tram_shift = tram_shift;
> > >  }
> > >  
> > > -static int snd_emu10k1_fx8010_playback_transfer(struct snd_pcm_substream *substream)
> > > +static int snd_emu10k1_fx8010_playback_transfer(struct snd_pcm_substream *substream,
> > > +						unsigned int ack_attr)
> > >  {
> > >  	struct snd_emu10k1 *emu = snd_pcm_substream_chip(substream);
> > >  	struct snd_emu10k1_fx8010_pcm *pcm = &emu->fx8010.pcm[substream->number];
> > >  
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	snd_pcm_indirect_playback_transfer(substream, &pcm->pcm_rec, fx8010_pb_trans_copy);
> > >  	return 0;
> > >  }
> > > @@ -1710,7 +1714,7 @@ static int snd_emu10k1_fx8010_playback_trigger(struct snd_pcm_substream *substre
> > >  		result = snd_emu10k1_fx8010_register_irq_handler(emu, snd_emu10k1_fx8010_playback_irq, pcm->gpr_running, substream, &pcm->irq);
> > >  		if (result < 0)
> > >  			goto __err;
> > > -		snd_emu10k1_fx8010_playback_transfer(substream);	/* roll the ball */
> > > +		snd_emu10k1_fx8010_playback_transfer(substream, SND_PCM_ACK_LEGACY);	/* roll the ball */
> > >  		snd_emu10k1_ptr_write(emu, emu->gpr_base + pcm->gpr_trigger, 0, 1);
> > >  		break;
> > >  	case SNDRV_PCM_TRIGGER_STOP:
> > > diff --git a/sound/pci/rme32.c b/sound/pci/rme32.c
> > > index 96d15db65dfd..3fd8de5bab26 100644
> > > --- a/sound/pci/rme32.c
> > > +++ b/sound/pci/rme32.c
> > > @@ -1092,7 +1092,7 @@ static int snd_rme32_capture_prepare(struct snd_pcm_substream *substream)
> > >  	if (cmd == SNDRV_PCM_TRIGGER_START && rme32->fullduplex_mode) {
> > >  		snd_pcm_group_for_each_entry(s, substream) {
> > >  			if (s == rme32->playback_substream) {
> > > -				s->ops->ack(s);
> > > +				s->ops->ack(s, SND_PCM_ACK_LEGACY);
> > >  				break;
> > >  			}
> > >  		}
> > > @@ -1145,11 +1145,15 @@ static void snd_rme32_pb_trans_copy(struct snd_pcm_substream *substream,
> > >  		    substream->runtime->dma_area + rec->sw_data, bytes);
> > >  }
> > >  
> > > -static int snd_rme32_playback_fd_ack(struct snd_pcm_substream *substream)
> > > +static int snd_rme32_playback_fd_ack(struct snd_pcm_substream *substream,
> > > +				     unsigned int ack_attr)
> > >  {
> > >  	struct rme32 *rme32 = snd_pcm_substream_chip(substream);
> > >  	struct snd_pcm_indirect *rec, *cprec;
> > >  
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	rec = &rme32->playback_pcm;
> > >  	cprec = &rme32->capture_pcm;
> > >  	spin_lock(&rme32->lock);
> > > @@ -1171,9 +1175,14 @@ static void snd_rme32_cp_trans_copy(struct snd_pcm_substream *substream,
> > >  		      bytes);
> > >  }
> > >  
> > > -static int snd_rme32_capture_fd_ack(struct snd_pcm_substream *substream)
> > > +static int snd_rme32_capture_fd_ack(struct snd_pcm_substream *substream,
> > > +					unsigned int ack_attr)
> > >  {
> > >  	struct rme32 *rme32 = snd_pcm_substream_chip(substream);
> > > +
> > > +	if (!(ack_attr & SND_PCM_ACK_LEGACY))
> > > +		return 0;
> > > +
> > >  	snd_pcm_indirect_capture_transfer(substream, &rme32->capture_pcm,
> > >  					  snd_rme32_cp_trans_copy);
> > >  	return 0;
> > > -- 
> > > 1.9.1
> > > 
> > _______________________________________________
> > Alsa-devel mailing list
> > Alsa-devel@alsa-project.org
> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 
> -- 

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