ALSA: usb-audio: UAC2: do clock validity check earlier

Move the check that parse_audio_format_rates_v2() do after
receiving the clock source entity ID directly into the find
function and add a validation flag to the function.

This patch does not introduce any logic flow change.

It is provided to allow introducing automatic clock switching
easier later. By moving this uac_clock_source_is_valid callsite,
2 additional callsites can be avoided.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

3 files changed, 21 insertions, 18 deletions

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 013b346f045d..0c98f52a1c9c 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -131,7 +131,8 @@ static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
 }
 
 static int __uac_clock_find_source(struct snd_usb_audio *chip,
-                                   int entity_id, unsigned long *visited)
+                                   int entity_id, unsigned long *visited,
+                                   bool validate)
 {
         struct uac_clock_source_descriptor *source;
         struct uac_clock_selector_descriptor *selector;
@@ -148,8 +149,15 @@ 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(chip->ctrl_intf, entity_id);
-        if (source)
-                return source->bClockID;
+        if (source) {
+                entity_id = source->bClockID;
+                if (validate && !uac_clock_source_is_valid(chip, entity_id)) {
+                        snd_printk(KERN_ERR "usb-audio:%d: clock source %d is not valid, cannot use\n",
+                                   chip->dev->devnum, entity_id);
+                        return -ENXIO;
+                }
+                return entity_id;
+        }
 
         selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
         if (selector) {
@@ -164,7 +172,7 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                 /* Selector values are one-based */
 
                 if (ret > selector->bNrInPins || ret < 1) {
-                        printk(KERN_ERR
+                        snd_printk(KERN_ERR
                                 "%s(): selector reported illegal value, id %d, ret %d\n",
                                 __func__, selector->bClockID, ret);
 
@@ -172,14 +180,14 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                 }
 
                 return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
-                                               visited);
+                                               visited, validate);
         }
 
         /* FIXME: multipliers only act as pass-thru element for now */
         multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
         if (multiplier)
                 return __uac_clock_find_source(chip, multiplier->bCSourceID,
-                                                visited);
+                                                visited, validate);
 
         return -EINVAL;
 }
@@ -195,11 +203,12 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
  *
  * 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)
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+                              bool validate)
 {
         DECLARE_BITMAP(visited, 256);
         memset(visited, 0, sizeof(visited));
-        return __uac_clock_find_source(chip, entity_id, visited);
+        return __uac_clock_find_source(chip, entity_id, visited, validate);
 }
 
 static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
@@ -275,18 +284,11 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
         struct usb_device *dev = chip->dev;
         __le32 data;
         int err, cur_rate, prev_rate;
-        int clock = snd_usb_clock_find_source(chip, fmt->clock);
+        int clock = snd_usb_clock_find_source(chip, fmt->clock, true);
 
         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;
-        }
-
         prev_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
 
         data = cpu_to_le32(rate);
diff --git a/sound/usb/clock.h b/sound/usb/clock.h
index 46630936d31f..d592e4a29856 100644
--- a/sound/usb/clock.h
+++ b/sound/usb/clock.h
@@ -5,6 +5,7 @@ int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
                              struct usb_host_interface *alts,
                              struct audioformat *fmt, int rate);
 
-int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id);
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+                             bool validate);
 
 #endif /* __USBAUDIO_CLOCK_H */
diff --git a/sound/usb/format.c b/sound/usb/format.c
index a695cafc0599..20c775170959 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -280,7 +280,7 @@ static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
         struct usb_device *dev = chip->dev;
         unsigned char tmp[2], *data;
         int nr_triplets, data_size, ret = 0;
-        int clock = snd_usb_clock_find_source(chip, fp->clock);
+        int clock = snd_usb_clock_find_source(chip, fp->clock, false);
 
         if (clock < 0) {
                 snd_printk(KERN_ERR "%s(): unable to find clock source (clock %d)\n",