ALSA: line6: Do clipping in volume / monitor manipulations

Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 7 insertions, 3 deletions

diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c
index 750d91dced57..cbcd97f5d629 100644
--- a/sound/usb/line6/playback.c
+++ b/sound/usb/line6/playback.c
@@ -37,7 +37,8 @@ static void change_volume(struct urb *urb_out, int volume[],
                 buf_end = p + urb_out->transfer_buffer_length / sizeof(*p);
 
                 for (; p < buf_end; ++p) {
-                        *p = (*p * volume[chn & 1]) >> 8;
+                        int val = (*p * volume[chn & 1]) >> 8;
+                        *p = clamp(val, 0x7fff, -0x8000);
                         ++chn;
                 }
         } else if (bytes_per_frame == 6) {
@@ -51,6 +52,7 @@ static void change_volume(struct urb *urb_out, int volume[],
 
                         val = p[0] + (p[1] << 8) + ((signed char)p[2] << 16);
                         val = (val * volume[chn & 1]) >> 8;
+                        val = clamp(val, 0x7fffff, -0x800000);
                         p[0] = val;
                         p[1] = val >> 8;
                         p[2] = val >> 16;
@@ -118,8 +120,10 @@ static void add_monitor_signal(struct urb *urb_out, unsigned char *signal,
                 po = (short *)urb_out->transfer_buffer;
                 buf_end = po + urb_out->transfer_buffer_length / sizeof(*po);
 
-                for (; po < buf_end; ++pi, ++po)
-                        *po += (*pi * volume) >> 8;
+                for (; po < buf_end; ++pi, ++po) {
+                        int val = *po + ((*pi * volume) >> 8);
+                        *po = clamp(val, 0x7fff, -0x8000);
+                }
         }
 
         /*