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ALSA: usb-audio: work around corrupted TEAC UD-H01 feedback data
commit 7040b6d1febfdbd9c1595efb751d492cd2503f96 upstream. The TEAC UD-H01 firmware sends wrong feedback frequency values, thus causing the PC to send the samples at a wrong rate, which results in clicks and crackles in the output. Add a workaround to detect and fix the corruption. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> [mick37@gmx.de: use sender->udh01_fb_quirk rather than ep->udh01_fb_quirk in snd_usb_handle_sync_urb()] Reported-and-tested-by: Mick <mick37@gmx.de> Reported-and-tested-by: Andrea Messa <andr.messa@tiscali.it> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2 changed files with 15 additions and 1 deletions
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@ -90,6 +90,7 @@ struct snd_usb_endpoint {
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unsigned int curframesize; /* current packet size in frames (for capture) */
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unsigned int syncmaxsize; /* sync endpoint packet size */
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unsigned int fill_max:1; /* fill max packet size always */
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unsigned int udh01_fb_quirk:1; /* corrupted feedback data */
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unsigned int datainterval; /* log_2 of data packet interval */
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unsigned int syncinterval; /* P for adaptive mode, 0 otherwise */
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unsigned char silence_value;
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@ -467,6 +467,10 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
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ep->syncinterval = 3;
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ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
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if (chip->usb_id == USB_ID(0x0644, 0x8038) /* TEAC UD-H01 */ &&
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ep->syncmaxsize == 4)
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ep->udh01_fb_quirk = 1;
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}
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list_add_tail(&ep->list, &chip->ep_list);
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@ -1075,7 +1079,16 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
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if (f == 0)
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return;
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if (unlikely(ep->freqshift == INT_MIN)) {
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if (unlikely(sender->udh01_fb_quirk)) {
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/*
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* The TEAC UD-H01 firmware sometimes changes the feedback value
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* by +/- 0x1.0000.
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*/
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if (f < ep->freqn - 0x8000)
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f += 0x10000;
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else if (f > ep->freqn + 0x8000)
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f -= 0x10000;
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} else if (unlikely(ep->freqshift == INT_MIN)) {
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/*
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* The first time we see a feedback value, determine its format
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* by shifting it left or right until it matches the nominal
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