[alsa-devel] [PATCH 3/4] ALSA: usb-audio: parse UAC2 endpoint descriptors correctly
Daniel Mack
daniel at caiaq.de
Wed May 26 18:17:46 CEST 2010
On Wed, May 26, 2010 at 06:11:38PM +0200, Daniel Mack wrote:
> UAC2 devices have their information about pitch control stored in a
> different field. Parse it, and emulate the bits for a v1 device.
>
> A new struct uac2_iso_endpoint_descriptor is added.
>
> Signed-off-by: Daniel Mack <daniel at caiaq.de>
> ---
> include/linux/usb/audio-v2.h | 16 ++++++++++++
Greg, I copied you because of this patch, just to let you know we're
having fun in your area of responsibility again :)
Daniel
> sound/usb/endpoint.c | 55 ++++++++++++++++++++++++++++++++----------
> 2 files changed, 58 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
> index 2389f93..92f1d99 100644
> --- a/include/linux/usb/audio-v2.h
> +++ b/include/linux/usb/audio-v2.h
> @@ -105,6 +105,22 @@ struct uac_as_header_descriptor_v2 {
> __u8 iChannelNames;
> } __attribute__((packed));
>
> +/* 4.10.1.2 Class-Specific AS Isochronous Audio Data Endpoint Descriptor */
> +
> +struct uac2_iso_endpoint_descriptor {
> + __u8 bLength; /* in bytes: 8 */
> + __u8 bDescriptorType; /* USB_DT_CS_ENDPOINT */
> + __u8 bDescriptorSubtype; /* EP_GENERAL */
> + __u8 bmAttributes;
> + __u8 bmControls;
> + __u8 bLockDelayUnits;
> + __le16 wLockDelay;
> +} __attribute__((packed));
> +
> +#define UAC2_CONTROL_PITCH (3 << 0)
> +#define UAC2_CONTROL_DATA_OVERRUN (3 << 2)
> +#define UAC2_CONTROL_DATA_UNDERRUN (3 << 4)
> +
> /* 6.1 Interrupt Data Message */
>
> #define UAC2_INTERRUPT_DATA_MSG_VENDOR (1 << 0)
> diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
> index 4887342..28ee1ce 100644
> --- a/sound/usb/endpoint.c
> +++ b/sound/usb/endpoint.c
> @@ -149,6 +149,47 @@ int snd_usb_add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct au
> return 0;
> }
>
> +static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
> + struct usb_host_interface *alts,
> + int protocol, int iface_no)
> +{
> + /* parsed with a v1 header here. that's ok as we only look at the
> + * header first which is the same for both versions */
> + struct uac_iso_endpoint_descriptor *csep;
> + struct usb_interface_descriptor *altsd = get_iface_desc(alts);
> + int attributes = 0;
> +
> + csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
> +
> + /* Creamware Noah has this descriptor after the 2nd endpoint */
> + if (!csep && altsd->bNumEndpoints >= 2)
> + csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
> +
> + if (!csep || csep->bLength < 7 ||
> + csep->bDescriptorSubtype != UAC_EP_GENERAL) {
> + snd_printk(KERN_WARNING "%d:%u:%d : no or invalid"
> + " class specific endpoint descriptor\n",
> + chip->dev->devnum, iface_no,
> + altsd->bAlternateSetting);
> + return 0;
> + }
> +
> + if (protocol == UAC_VERSION_1) {
> + attributes = csep->bmAttributes;
> + } else {
> + struct uac2_iso_endpoint_descriptor *csep2 =
> + (struct uac2_iso_endpoint_descriptor *) csep;
> +
> + attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
> +
> + /* emulate the endpoint attributes of a v1 device */
> + if (csep2->bmControls & UAC2_CONTROL_PITCH)
> + attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
> + }
> +
> + return attributes;
> +}
> +
> int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
> {
> struct usb_device *dev;
> @@ -158,7 +199,6 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
> int i, altno, err, stream;
> int format = 0, num_channels = 0;
> struct audioformat *fp = NULL;
> - unsigned char *csep;
> int num, protocol;
> struct uac_format_type_i_continuous_descriptor *fmt;
>
> @@ -279,17 +319,6 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
> fp->maxpacksize * 2)
> continue;
>
> - csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
> - /* Creamware Noah has this descriptor after the 2nd endpoint */
> - if (!csep && altsd->bNumEndpoints >= 2)
> - csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
> - if (!csep || csep[0] < 7 || csep[2] != UAC_EP_GENERAL) {
> - snd_printk(KERN_WARNING "%d:%u:%d : no or invalid"
> - " class specific endpoint descriptor\n",
> - dev->devnum, iface_no, altno);
> - csep = NULL;
> - }
> -
> fp = kzalloc(sizeof(*fp), GFP_KERNEL);
> if (! fp) {
> snd_printk(KERN_ERR "cannot malloc\n");
> @@ -308,7 +337,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
> if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
> fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
> * (fp->maxpacksize & 0x7ff);
> - fp->attributes = csep ? csep[3] : 0;
> + fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
>
> /* some quirks for attributes here */
>
> --
> 1.7.1
>
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