From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Mack Subject: [PATCH 5/6] ALSA: snd-usb: add support for implicit feedback Date: Fri, 23 Dec 2011 17:15:46 +0100 Message-ID: <1324656947-23169-6-git-send-email-zonque@gmail.com> References: <1324656947-23169-1-git-send-email-zonque@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail.zonque.de (svenfoo.org [82.94.215.22]) by alsa0.perex.cz (Postfix) with ESMTP id DA90E103FDA for ; Fri, 23 Dec 2011 17:16:07 +0100 (CET) In-Reply-To: <1324656947-23169-1-git-send-email-zonque@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: alsa-devel@alsa-project.org Cc: gdiffey@gmail.com, tiwai@suse.de, clemens@ladisch.de, linuxaudio@showlabor.de, Daniel Mack , blablack@gmail.com List-Id: alsa-devel@alsa-project.org Implicit feedback is a streaming mode that does not rely on dedicated sync endpoints but uses the information provided by record streams to clock output streams. Now that the streaming logic is decoupled from the PCM streams, this is easy to implement. Signed-off-by: Daniel Mack --- sound/usb/pcm.c | 37 ++++++++++++++++++++++++++----------- 1 files changed, 26 insertions(+), 11 deletions(-) diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 271579c..69cc912 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -300,7 +300,7 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt) struct usb_interface *iface; unsigned int ep, attr; int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK; - int err; + int err, implicit_fb = 0; iface = usb_ifnum_to_if(dev, fmt->iface); if (WARN_ON(!iface)) @@ -325,25 +325,34 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt) * assume it as adaptive-out or sync-in. */ attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE; - if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) || - (! is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) && - altsd->bNumEndpoints >= 2) { - switch (subs->stream->chip->usb_id) { - case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */ - case USB_ID(0x0763, 0x2081): + + switch (subs->stream->chip->usb_id) { + case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */ + case USB_ID(0x0763, 0x2081): + if (is_playback) { + implicit_fb = 1; ep = 0x81; iface = usb_ifnum_to_if(dev, 2); + + if (!iface || iface->num_altsetting == 0) + return -EINVAL; + alts = &iface->altsetting[1]; goto add_sync_ep; } + } + if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) || + (!is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) && + altsd->bNumEndpoints >= 2) { /* check sync-pipe endpoint */ /* ... and check descriptor size before accessing bSynchAddress because there is a version of the SB Audigy 2 NX firmware lacking the audio fields in the endpoint descriptors */ if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 || (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE && - get_endpoint(alts, 1)->bSynchAddress != 0)) { + get_endpoint(alts, 1)->bSynchAddress != 0 && + !implicit_fb)) { snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n", dev->devnum, fmt->iface, fmt->altsetting); return -EINVAL; @@ -351,16 +360,22 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt) ep = get_endpoint(alts, 1)->bEndpointAddress; if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE && (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) || - (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) { + (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)) || + ( is_playback && !implicit_fb))) { snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n", dev->devnum, fmt->iface, fmt->altsetting); return -EINVAL; } + + implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK) + == USB_ENDPOINT_USAGE_IMPLICIT_FB; + add_sync_ep: subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip, alts, ep, !subs->direction, - SND_USB_ENDPOINT_TYPE_SYNC); - + implicit_fb ? + SND_USB_ENDPOINT_TYPE_DATA : + SND_USB_ENDPOINT_TYPE_SYNC); if (!subs->sync_endpoint) return -EINVAL; -- 1.7.7.4