ALSA: usb - Remove trailing spaces from USB card name strings

Some USB devices give trailing spaces in strings returned from
usb_string().  This confuses the automatic card-id creation, resulting
always in "default".
This patch fixes the behavior by removing trailing spaces.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 18 insertions, 4 deletions

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 40722f8711ad..a90662af2d6b 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -41,6 +41,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/ctype.h>
 #include <linux/usb.h>
 #include <linux/moduleparam.h>
 #include <linux/mutex.h>
@@ -283,6 +284,15 @@ static int snd_usb_audio_dev_free(struct snd_device *device)
         return snd_usb_audio_free(chip);
 }
 
+static void remove_trailing_spaces(char *str)
+{
+        char *p;
+
+        if (!*str)
+                return;
+        for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
+                *p = 0;
+}
 
 /*
  * create a chip instance and set its names.
@@ -351,7 +361,7 @@ static int snd_usb_audio_create(struct usb_device *dev, int idx,
         snd_component_add(card, component);
 
         /* retrieve the device string as shortname */
-        if (quirk && quirk->product_name) {
+        if (quirk && quirk->product_name && *quirk->product_name) {
                 strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
         } else {
                 if (!dev->descriptor.iProduct ||
@@ -363,9 +373,10 @@ static int snd_usb_audio_create(struct usb_device *dev, int idx,
                                 USB_ID_PRODUCT(chip->usb_id));
                 }
         }
+        remove_trailing_spaces(card->shortname);
 
         /* retrieve the vendor and device strings as longname */
-        if (quirk && quirk->vendor_name) {
+        if (quirk && quirk->vendor_name && *quirk->vendor_name) {
                 len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
         } else {
                 if (dev->descriptor.iManufacturer)
@@ -375,8 +386,11 @@ static int snd_usb_audio_create(struct usb_device *dev, int idx,
                         len = 0;
                 /* we don't really care if there isn't any vendor string */
         }
-        if (len > 0)
-                strlcat(card->longname, " ", sizeof(card->longname));
+        if (len > 0) {
+                remove_trailing_spaces(card->longname);
+                if (*card->longname)
+                        strlcat(card->longname, " ", sizeof(card->longname));
+        }
 
         strlcat(card->longname, card->shortname, sizeof(card->longname));