* Why is substream->pcm->dev == NULL?
@ 2008-08-07 18:51 Timur Tabi
2008-08-08 5:58 ` Takashi Iwai
0 siblings, 1 reply; 2+ messages in thread
From: Timur Tabi @ 2008-08-07 18:51 UTC (permalink / raw)
To: ALSA development
In my _pointer callback function, I have this:
printk(KERN_INFO "%s:%u substream->pcm->dev=%p, substream->pcm->card->dev=%p\n",
__func__, __LINE__, substream->pcm->dev, substream->pcm->card->dev);
During playback, it displays this:
fsl_dma_pointer:698 substream->pcm->dev=00000000, substream->pcm->card->dev=dfa50a08
Why is substream->pcm->dev == NULL? What's the point of having this field if
you're not going to use it?
--
Timur Tabi
Linux kernel developer at Freescale
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Why is substream->pcm->dev == NULL?
2008-08-07 18:51 Why is substream->pcm->dev == NULL? Timur Tabi
@ 2008-08-08 5:58 ` Takashi Iwai
0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2008-08-08 5:58 UTC (permalink / raw)
To: Timur Tabi; +Cc: ALSA development
At Thu, 07 Aug 2008 13:51:55 -0500,
Timur Tabi wrote:
>
> In my _pointer callback function, I have this:
>
> printk(KERN_INFO "%s:%u substream->pcm->dev=%p, substream->pcm->card->dev=%p\n",
> __func__, __LINE__, substream->pcm->dev, substream->pcm->card->dev);
>
> During playback, it displays this:
>
> fsl_dma_pointer:698 substream->pcm->dev=00000000, substream->pcm->card->dev=dfa50a08
>
> Why is substream->pcm->dev == NULL? What's the point of having this field if
> you're not going to use it?
It's provided to use a different device for PCM than card->dev.
An example is found in AOA drivers.
Takashi
^ permalink raw reply [flat|nested] 2+ messages in thread
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2008-08-07 18:51 Why is substream->pcm->dev == NULL? Timur Tabi
2008-08-08 5:58 ` Takashi Iwai
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