At Thu, 5 Mar 2015 13:21:49 +0300, Dan Carpenter wrote:
Hello Takashi Iwai,
The patch 0416980d0a2b: "ALSA: line6: Fix volume calculation for big-endian" from Jan 28, 2015, leads to the following static checker warning:
sound/usb/line6/playback.c:42 change_volume() warn: always clamps to s16min sound/usb/line6/playback.c:57 change_volume() warn: always clamps to (-8388608) sound/usb/line6/playback.c:129 add_monitor_signal() warn: always clamps to s16min
sound/usb/line6/playback.c 25 static void change_volume(struct urb *urb_out, int volume[], 26 int bytes_per_frame) 27 { 28 int chn = 0; 29 30 if (volume[0] == 256 && volume[1] == 256) 31 return; /* maximum volume - no change */ 32 33 if (bytes_per_frame == 4) { 34 __le16 *p, *buf_end; 35 36 p = (__le16 *)urb_out->transfer_buffer; 37 buf_end = p + urb_out->transfer_buffer_length / sizeof(*p); 38 39 for (; p < buf_end; ++p) { 40 short pv = le16_to_cpu(*p); 41 int val = (pv * volume[chn & 1]) >> 8; 42 pv = clamp(val, 0x7fff, -0x8000); ^^^^^^^^^^^^^^^^ You didn't really add this, but you might know what was intended here. It is a complete mystery to me. :)
No mystery, just left/right swapped. It's a common mistake, and you'll feel the same when you go from Paris to London and look at a street. I'll fix them (the code, not the street).
thanks,
Takashi