[alsa-devel] [PATCH v2 1/7] ALSA: line6: Fix volume calculation for big-endian

Takashi Iwai tiwai at suse.de
Wed Jan 28 17:54:28 CET 2015


Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
v1->v2: fix the type to __le16, as sparse warns

 sound/usb/line6/playback.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c
index 1708c05f14db..3226422d2858 100644
--- a/sound/usb/line6/playback.c
+++ b/sound/usb/line6/playback.c
@@ -31,14 +31,16 @@ static void change_volume(struct urb *urb_out, int volume[],
 		return;		/* maximum volume - no change */
 
 	if (bytes_per_frame == 4) {
-		short *p, *buf_end;
+		__le16 *p, *buf_end;
 
 		p = (short *)urb_out->transfer_buffer;
 		buf_end = p + urb_out->transfer_buffer_length / sizeof(*p);
 
 		for (; p < buf_end; ++p) {
-			int val = (*p * volume[chn & 1]) >> 8;
-			*p = clamp(val, 0x7fff, -0x8000);
+			short pv = le16_to_cpu(*p);
+			int val = (pv * volume[chn & 1]) >> 8;
+			pv = clamp(val, 0x7fff, -0x8000);
+			*p = cpu_to_le16(pv);
 			++chn;
 		}
 	} else if (bytes_per_frame == 6) {
@@ -114,15 +116,18 @@ static void add_monitor_signal(struct urb *urb_out, unsigned char *signal,
 		return;		/* zero volume - no change */
 
 	if (bytes_per_frame == 4) {
-		short *pi, *po, *buf_end;
+		__le16 *pi, *po, *buf_end;
 
 		pi = (short *)signal;
 		po = (short *)urb_out->transfer_buffer;
 		buf_end = po + urb_out->transfer_buffer_length / sizeof(*po);
 
 		for (; po < buf_end; ++pi, ++po) {
-			int val = *po + ((*pi * volume) >> 8);
-			*po = clamp(val, 0x7fff, -0x8000);
+			short pov = le16_to_cpu(*po);
+			short piv = le16_to_cpu(*pi);
+			int val = pov + ((piv * volume) >> 8);
+			pov = clamp(val, 0x7fff, -0x8000);
+			*po = cpu_to_le16(pov);
 		}
 	}
 
-- 
2.2.2



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