From c8491535d7f1a1e8f7f3e0d31e8f7525809c98a1 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 23 Jan 2015 16:54:36 +0100 Subject: [PATCH] ALSA: line6: Do clipping in volume / monitor manipulations Tested-by: Chris Rorvick Signed-off-by: Takashi Iwai --- sound/usb/line6/playback.c | 10 +++++++--- 1 file 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); + } } /* -- 2.20.1