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authorClemens Ladisch <clemens@ladisch.de>2013-02-03 22:31:20 +0100
committerClemens Ladisch <clemens@ladisch.de>2013-06-27 21:59:47 +0200
commitba7c2be114243fa4cfcbc66a81db18e1d55abf4b (patch)
tree0452886296dc4564d4ca7cd5105231d74e97d88a /sound/usb/pcm.c
parent8f898e92aea2c24c7f379ee265d178f69ebb9c07 (diff)
downloadlinux-ba7c2be114243fa4cfcbc66a81db18e1d55abf4b.tar.bz2
ALSA: usb-audio: detect implicit feedback on Roland devices
All the Roland/Edirol/BOSS USB audio devices that need implicit feedback show this unambiguously in their descriptors, so it might be a good idea to let the driver detect this. This should make playback work correctly (at least with Jack) with the following devices: - BOSS GT-100 - BOSS JS-8 Jam Station - Edirol M-16DX - Roland GAIA SH-01 Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Diffstat (limited to 'sound/usb/pcm.c')
-rw-r--r--sound/usb/pcm.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 776c58c7cba0..15b151ed4899 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -298,6 +298,35 @@ static int deactivate_endpoints(struct snd_usb_substream *subs)
return 0;
}
+static int search_roland_implicit_fb(struct usb_device *dev, int ifnum,
+ unsigned int altsetting,
+ struct usb_host_interface **alts,
+ unsigned int *ep)
+{
+ struct usb_interface *iface;
+ struct usb_interface_descriptor *altsd;
+ struct usb_endpoint_descriptor *epd;
+
+ iface = usb_ifnum_to_if(dev, ifnum);
+ if (!iface || iface->num_altsetting < altsetting + 1)
+ return -ENOENT;
+ *alts = &iface->altsetting[altsetting];
+ altsd = get_iface_desc(*alts);
+ if (altsd->bAlternateSetting != altsetting ||
+ altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
+ (altsd->bInterfaceSubClass != 2 &&
+ altsd->bInterfaceProtocol != 2 ) ||
+ altsd->bNumEndpoints < 1)
+ return -ENOENT;
+ epd = get_endpoint(*alts, 0);
+ if (!usb_endpoint_is_isoc_in(epd) ||
+ (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
+ USB_ENDPOINT_USAGE_IMPLICIT_FB)
+ return -ENOENT;
+ *ep = epd->bEndpointAddress;
+ return 0;
+}
+
/*
* find a matching format and set up the interface
*/
@@ -393,6 +422,18 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
goto add_sync_ep;
}
}
+ if (is_playback &&
+ attr == USB_ENDPOINT_SYNC_ASYNC &&
+ altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
+ altsd->bInterfaceProtocol == 2 &&
+ altsd->bNumEndpoints == 1 &&
+ USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
+ search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
+ altsd->bAlternateSetting,
+ &alts, &ep) >= 0) {
+ implicit_fb = 1;
+ goto add_sync_ep;
+ }
if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
(!is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&