ALSA: usb: Work around CM6631 sample rate change bug

[platform/adaptation/renesas_rcar/renesas_kernel.git] / sound / usb / clock.c

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 5e634a2..9e2703a 100644 (file)
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -253,7 +253,7 @@ 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 err, cur_rate, prev_rate;
        int clock = snd_usb_clock_find_source(chip, fmt->clock);
 
        if (clock < 0)
@@ -266,6 +266,19 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
                return -ENXIO;
        }
 
+       err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+                             USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+                             UAC2_CS_CONTROL_SAM_FREQ << 8,
+                             snd_usb_ctrl_intf(chip) | (clock << 8),
+                             data, sizeof(data));
+       if (err < 0) {
+               snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
+                          dev->devnum, iface, fmt->altsetting);
+               prev_rate = 0;
+       } else {
+               prev_rate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+       }
+
        data[0] = rate;
        data[1] = rate >> 8;
        data[2] = rate >> 16;
@@ -280,19 +293,31 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
                return err;
        }
 
-       if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
-                                  USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
-                                  UAC2_CS_CONTROL_SAM_FREQ << 8,
-                                  snd_usb_ctrl_intf(chip) | (clock << 8),
-                                  data, sizeof(data))) < 0) {
+       err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+                             USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+                             UAC2_CS_CONTROL_SAM_FREQ << 8,
+                             snd_usb_ctrl_intf(chip) | (clock << 8),
+                             data, sizeof(data));
+       if (err < 0) {
                snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
                           dev->devnum, iface, fmt->altsetting);
-               return err;
+               cur_rate = 0;
+       } else {
+               cur_rate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
        }
 
-       crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
-       if (crate != rate)
-               snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
+       if (cur_rate != rate) {
+               snd_printd(KERN_WARNING
+                          "current rate %d is different from the runtime rate %d\n",
+                          cur_rate, rate);
+       }
+
+       /* Some devices doesn't respond to sample rate changes while the
+        * interface is active. */
+       if (rate != prev_rate) {
+               usb_set_interface(dev, iface, 0);
+               usb_set_interface(dev, iface, fmt->altsetting);
+       }
 
        return 0;
 }