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Commit 50cdbf15 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela
Browse files

[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: default avatarClemens Ladisch <clemens@ladisch.de>
parent 7291548d

sound/usb/usbaudio.c

+9 −13
Original line number Diff line number Diff line
@@ -452,18 +452,12 @@ static int retire_playback_sync_urb(snd_usb_substream_t *subs, 
	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;

		}

#endif

		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;

}
@@ -484,10 +478,12 @@ static int retire_playback_sync_urb_hs(snd_usb_substream_t *subs, 
	if (urb->iso_frame_desc[0].status == 0 &&

	    urb->iso_frame_desc[0].actual_length == 4) {

		f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff;

		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;

}