ALSA: usb-audio: parse UAC2 endpoint descriptors correctly
Daniel Mack [Wed, 26 May 2010 16:11:38 +0000 (18:11 +0200)]
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@caiaq.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/linux/usb/audio-v2.h
sound/usb/endpoint.c

index 2389f93..92f1d99 100644 (file)
@@ -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)
index 4887342..28ee1ce 100644 (file)
@@ -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 */