| From 7040b6d1febfdbd9c1595efb751d492cd2503f96 Mon Sep 17 00:00:00 2001 |
| From: Clemens Ladisch <clemens@ladisch.de> |
| Date: Thu, 1 May 2014 12:20:22 +0200 |
| Subject: ALSA: usb-audio: work around corrupted TEAC UD-H01 feedback data |
| |
| From: Clemens Ladisch <clemens@ladisch.de> |
| |
| 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> |
| |
| --- |
| sound/usb/card.h | 1 + |
| sound/usb/endpoint.c | 15 ++++++++++++++- |
| 2 files changed, 15 insertions(+), 1 deletion(-) |
| |
| --- a/sound/usb/card.h |
| +++ b/sound/usb/card.h |
| @@ -90,6 +90,7 @@ struct snd_usb_endpoint { |
| unsigned int curframesize; /* current packet size in frames (for capture) */ |
| unsigned int syncmaxsize; /* sync endpoint packet size */ |
| unsigned int fill_max:1; /* fill max packet size always */ |
| + unsigned int udh01_fb_quirk:1; /* corrupted feedback data */ |
| unsigned int datainterval; /* log_2 of data packet interval */ |
| unsigned int syncinterval; /* P for adaptive mode, 0 otherwise */ |
| unsigned char silence_value; |
| --- a/sound/usb/endpoint.c |
| +++ b/sound/usb/endpoint.c |
| @@ -467,6 +467,10 @@ struct snd_usb_endpoint *snd_usb_add_end |
| ep->syncinterval = 3; |
| |
| ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize); |
| + |
| + if (chip->usb_id == USB_ID(0x0644, 0x8038) /* TEAC UD-H01 */ && |
| + ep->syncmaxsize == 4) |
| + ep->udh01_fb_quirk = 1; |
| } |
| |
| list_add_tail(&ep->list, &chip->ep_list); |
| @@ -1075,7 +1079,16 @@ void snd_usb_handle_sync_urb(struct snd_ |
| if (f == 0) |
| return; |
| |
| - if (unlikely(ep->freqshift == INT_MIN)) { |
| + if (unlikely(sender->udh01_fb_quirk)) { |
| + /* |
| + * The TEAC UD-H01 firmware sometimes changes the feedback value |
| + * by +/- 0x1.0000. |
| + */ |
| + if (f < ep->freqn - 0x8000) |
| + f += 0x10000; |
| + else if (f > ep->freqn + 0x8000) |
| + f -= 0x10000; |
| + } else if (unlikely(ep->freqshift == INT_MIN)) { |
| /* |
| * The first time we see a feedback value, determine its format |
| * by shifting it left or right until it matches the nominal |