[ALSA] usb-audio - sanity-check sync feedback frequency values
USB generic driver
Check that the synchronization feedback frequency values returned by the
device are more or less near the nominal frequency.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index c360ab9..a6ed0d0 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -452,17 +452,11 @@
if (urb->iso_frame_desc[0].status == 0 &&
urb->iso_frame_desc[0].actual_length == 3) {
f = combine_triple((u8*)urb->transfer_buffer) << 2;
-#if 0
- if (f < subs->freqn - (subs->freqn>>3) || f > subs->freqmax) {
- snd_printd(KERN_WARNING "requested frequency %d (%u,%03uHz) out of range (current nominal %d (%u,%03uHz))\n",
- f, f >> 14, (f & ((1 << 14) - 1) * 1000) / ((1 << 14) - 1),
- subs->freqn, subs->freqn >> 14, (subs->freqn & ((1 << 14) - 1) * 1000) / ((1 << 14) - 1));
- continue;
+ if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
+ spin_lock_irqsave(&subs->lock, flags);
+ subs->freqm = f;
+ spin_unlock_irqrestore(&subs->lock, flags);
}
-#endif
- spin_lock_irqsave(&subs->lock, flags);
- subs->freqm = f;
- spin_unlock_irqrestore(&subs->lock, flags);
}
return 0;
@@ -484,9 +478,11 @@
if (urb->iso_frame_desc[0].status == 0 &&
urb->iso_frame_desc[0].actual_length == 4) {
f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff;
- spin_lock_irqsave(&subs->lock, flags);
- subs->freqm = f;
- spin_unlock_irqrestore(&subs->lock, flags);
+ if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
+ spin_lock_irqsave(&subs->lock, flags);
+ subs->freqm = f;
+ spin_unlock_irqrestore(&subs->lock, flags);
+ }
}
return 0;