Messages in this thread | | | Subject | Re: [PATCH] ANDROID: sound: usb: Add vendor's hooking interface | From | Pierre-Louis Bossart <> | Date | Thu, 18 Jun 2020 07:27:07 -0500 |
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On 6/16/20 9:18 PM, JaeHun Jung wrote: > In mobile, a co-processor is used when using USB audio > to improve power consumption. > hooking is required for sync-up when operating > the co-processor. So register call-back function. > The main operation of the call-back function is as follows: > - Initialize the co-processor by transmitting data > when initializing. > - Change the co-processor setting value through > the interface function. > - Configure sampling rate > - pcm open/close
Thank you for this patch. With the removal of the 3.5mm jack on a number of platforms, and improvements to reduce power consumption on a variety of hosts there's indeed a need to enhance sound/usb in the kernel.
> > Bug: 156315379 > > Change-Id: I32e1dd408e64aaef68ee06c480c4b4d4c95546dc > Signed-off-by: JaeHun Jung <jh0801.jung@samsung.com>
You probably want to remove bug references and Change-Id if they are not publicly visible
> @@ -891,6 +897,15 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream) > struct usb_interface *iface; > int ret; > > + if (usb_audio_ops && usb_audio_ops->vendor_set_pcmbuf) { > + ret = usb_audio_ops->vendor_set_pcmbuf(subs->dev); > + > + if (ret < 0) { > + dev_err(&subs->dev->dev, "pcm buf transfer failed\n"); > + return ret; > + } > + } > + > if (! subs->cur_audiofmt) { > dev_err(&subs->dev->dev, "no format is specified!\n"); > return -ENXIO; > @@ -924,6 +939,15 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream) > if (ret < 0) > goto unlock; > > + if (usb_audio_ops && usb_audio_ops->vendor_set_rate) { > + subs->need_setup_ep = false; > + usb_audio_ops->vendor_set_rate( > + subs->cur_audiofmt->iface, > + subs->cur_rate, > + subs->cur_audiofmt->altsetting); > + goto unlock; > + } > + > ret = configure_endpoint(subs); > if (ret < 0) > goto unlock; > @@ -1333,6 +1357,9 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) > struct snd_usb_substream *subs = &as->substream[direction]; > int ret; > > + if (usb_audio_ops && usb_audio_ops->vendor_pcm_con) > + usb_audio_ops->vendor_pcm_con(true, direction); > + > subs->interface = -1; > subs->altset_idx = 0; > runtime->hw = snd_usb_hardware; > @@ -1361,12 +1388,18 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream) > struct snd_usb_substream *subs = &as->substream[direction]; > int ret; > > + if (usb_audio_ops && usb_audio_ops->vendor_pcm_con) > + usb_audio_ops->vendor_pcm_con(false, direction); > +
can you elaborate on the PCM streaming parts? if you allocate a buffer for the co-processor to deal with PCM data, will you end-up copying data from the existing ring buffers allocated with vmalloc() into your coprocessor?
I was instead thinking of having a different 'mode' where the PCM buffers are not allocated by sound/usb, but instead allocated by the driver taking care of the low-power USB path, so that apps can directly write into ring buffers that are handled by the coprocessor/offload unit.
Thanks -Pierre
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