1 files changed, 25 insertions, 34 deletions

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index b5855114667e..b853f8df794f 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -19,33 +19,19 @@
 
 #include <linux/bitops.h>
 #include <linux/init.h>
-#include <linux/list.h>
-#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/usb.h>
-#include <linux/moduleparam.h>
-#include <linux/mutex.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
 
 #include <sound/core.h>
 #include <sound/info.h>
 #include <sound/pcm.h>
-#include <sound/pcm_params.h>
-#include <sound/initval.h>
 
 #include "usbaudio.h"
 #include "card.h"
-#include "midi.h"
-#include "mixer.h"
-#include "proc.h"
-#include "quirks.h"
-#include "endpoint.h"
 #include "helper.h"
-#include "debug.h"
-#include "pcm.h"
-#include "urb.h"
-#include "format.h"
+#include "clock.h"
 
 static struct uac_clock_source_descriptor *
         snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
@@ -134,10 +120,7 @@ static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
         return !!data;
 }
 
-/* Try to find the clock source ID of a given clock entity */
-
 static int __uac_clock_find_source(struct snd_usb_audio *chip,
-                                   struct usb_host_interface *host_iface,
                                    int entity_id, unsigned long *visited)
 {
         struct uac_clock_source_descriptor *source;
@@ -154,11 +137,11 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
         }
 
         /* first, see if the ID we're looking for is a clock source already */
-        source = snd_usb_find_clock_source(host_iface, entity_id);
+        source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
         if (source)
                 return source->bClockID;
 
-        selector = snd_usb_find_clock_selector(host_iface, entity_id);
+        selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
         if (selector) {
                 int ret;
 
@@ -168,6 +151,8 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                 if (ret < 0)
                         return ret;
 
+                /* Selector values are one-based */
+
                 if (ret > selector->bNrInPins || ret < 1) {
                         printk(KERN_ERR
                                 "%s(): selector reported illegal value, id %d, ret %d\n",
@@ -176,27 +161,35 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                         return -EINVAL;
                 }
 
-                return __uac_clock_find_source(chip, host_iface,
-                                               selector->baCSourceID[ret-1],
+                return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
                                                visited);
         }
 
         /* FIXME: multipliers only act as pass-thru element for now */
-        multiplier = snd_usb_find_clock_multiplier(host_iface, entity_id);
+        multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
         if (multiplier)
-                return __uac_clock_find_source(chip, host_iface,
-                                               multiplier->bCSourceID, visited);
+                return __uac_clock_find_source(chip, multiplier->bCSourceID,
+                                                visited);
 
         return -EINVAL;
 }
 
-int snd_usb_clock_find_source(struct snd_usb_audio *chip,
-                              struct usb_host_interface *host_iface,
-                              int entity_id)
+/*
+ * For all kinds of sample rate settings and other device queries,
+ * the clock source (end-leaf) must be used. However, clock selectors,
+ * clock multipliers and sample rate converters may be specified as
+ * clock source input to terminal. This functions walks the clock path
+ * to its end and tries to find the source.
+ *
+ * The 'visited' bitfield is used internally to detect recursive loops.
+ *
+ * Returns the clock source UnitID (>=0) on success, or an error.
+ */
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)
 {
         DECLARE_BITMAP(visited, 256);
         memset(visited, 0, sizeof(visited));
-        return __uac_clock_find_source(chip, host_iface, entity_id, visited);
+        return __uac_clock_find_source(chip, entity_id, visited);
 }
 
 static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
@@ -211,11 +204,8 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
         ep = get_endpoint(alts, 0)->bEndpointAddress;
 
         /* if endpoint doesn't have sampling rate control, bail out */
-        if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE)) {
-                snd_printk(KERN_WARNING "%d:%d:%d: endpoint lacks sample rate attribute bit, cannot set.\n",
-                                   dev->devnum, iface, fmt->altsetting);
+        if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
                 return 0;
-        }
 
         data[0] = rate;
         data[1] = rate >> 8;
@@ -254,12 +244,13 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
         struct usb_device *dev = chip->dev;
         unsigned char data[4];
         int err, crate;
-        int clock = snd_usb_clock_find_source(chip, chip->ctrl_intf, fmt->clock);
+        int clock = snd_usb_clock_find_source(chip, fmt->clock);
 
         if (clock < 0)
                 return clock;
 
         if (!uac_clock_source_is_valid(chip, clock)) {
+                /* TODO: should we try to find valid clock setups by ourself? */
                 snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use\n",
                            dev->devnum, iface, fmt->altsetting, clock);
                 return -ENXIO;