1 files changed, 55 insertions, 2 deletions

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 28ee1ce3971a..9593b91452b9 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -190,6 +190,38 @@ static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
         return attributes;
 }
 
+static struct uac2_input_terminal_descriptor *
+        snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+                                               int terminal_id)
+{
+        struct uac2_input_terminal_descriptor *term = NULL;
+
+        while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+                                               ctrl_iface->extralen,
+                                               term, UAC_INPUT_TERMINAL))) {
+                if (term->bTerminalID == terminal_id)
+                        return term;
+        }
+
+        return NULL;
+}
+
+static struct uac2_output_terminal_descriptor *
+        snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+                                                int terminal_id)
+{
+        struct uac2_output_terminal_descriptor *term = NULL;
+
+        while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+                                               ctrl_iface->extralen,
+                                               term, UAC_OUTPUT_TERMINAL))) {
+                if (term->bTerminalID == terminal_id)
+                        return term;
+        }
+
+        return NULL;
+}
+
 int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
 {
         struct usb_device *dev;
@@ -199,7 +231,7 @@ 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;
-        int num, protocol;
+        int num, protocol, clock = 0;
         struct uac_format_type_i_continuous_descriptor *fmt;
 
         dev = chip->dev;
@@ -263,6 +295,8 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
                 }
 
                 case UAC_VERSION_2: {
+                        struct uac2_input_terminal_descriptor *input_term;
+                        struct uac2_output_terminal_descriptor *output_term;
                         struct uac_as_header_descriptor_v2 *as =
                                 snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
 
@@ -281,7 +315,25 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
                         num_channels = as->bNrChannels;
                         format = le32_to_cpu(as->bmFormats);
 
-                        break;
+                        /* lookup the terminal associated to this interface
+                         * to extract the clock */
+                        input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
+                                                                            as->bTerminalLink);
+                        if (input_term) {
+                                clock = input_term->bCSourceID;
+                                break;
+                        }
+
+                        output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
+                                                                              as->bTerminalLink);
+                        if (output_term) {
+                                clock = output_term->bCSourceID;
+                                break;
+                        }
+
+                        snd_printk(KERN_ERR "%d:%u:%d : bogus bTerminalLink %d\n",
+                                   dev->devnum, iface_no, altno, as->bTerminalLink);
+                        continue;
                 }
 
                 default:
@@ -338,6 +390,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
                         fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
                                         * (fp->maxpacksize & 0x7ff);
                 fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
+                fp->clock = clock;
 
                 /* some quirks for attributes here */