[alsa-devel] [PATCH] Workaround for misdetected sample rate with CM6207
Summary: Workaround for misdetected sample rate with CM6207
The CM6207 incorrectly advertises its 96 kHz playback setting as 48 kHz in its USB device descriptor. This patch extends an existing workaround in usbaudio.c to also cover the CM6207.
This resolves issue 0004249 in the ALSA bug tracker.
Signed-off by: Joris van Rantwijk jorispubl@xs4all.nl
diff -ur linux-2.6.28.4/sound/usb/usbaudio.c linux-2.6.28.4_j/sound/usb/usbaudio.c --- linux-2.6.28.4/sound/usb/usbaudio.c 2009-02-13 21:45:17.000000000 +0100 +++ linux-2.6.28.4_j/sound/usb/usbaudio.c 2009-02-13 22:00:44.000000000 +0100 @@ -2533,19 +2533,20 @@ }
fp->nr_rates = nr_rates; - fp->rate_min = fp->rate_max = combine_triple(&fmt[8]); + fp->rate_min = fp->rate_max = 0; for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) { unsigned int rate = combine_triple(&fmt[idx]); /* C-Media CM6501 mislabels its 96 kHz altsetting */ if (rate == 48000 && nr_rates == 1 && - chip->usb_id == USB_ID(0x0d8c, 0x0201) && + (chip->usb_id == USB_ID(0x0d8c, 0x0201) || + chip->usb_id == USB_ID(0x0d8c, 0x0102)) && fp->altsetting == 5 && fp->maxpacksize == 392) rate = 96000; fp->rate_table[r] = rate; nonzero_rates |= rate; - if (rate < fp->rate_min) + if (r == 0 || rate < fp->rate_min) fp->rate_min = rate; - else if (rate > fp->rate_max) + else if (r == 0 || rate > fp->rate_max) fp->rate_max = rate; fp->rates |= snd_pcm_rate_to_rate_bit(rate); }
At Sat, 14 Feb 2009 22:22:05 +0100, Joris van Rantwijk wrote:
Summary: Workaround for misdetected sample rate with CM6207
The CM6207 incorrectly advertises its 96 kHz playback setting as 48 kHz in its USB device descriptor. This patch extends an existing workaround in usbaudio.c to also cover the CM6207.
This resolves issue 0004249 in the ALSA bug tracker.
Signed-off by: Joris van Rantwijk jorispubl@xs4all.nl
Thanks for the patch. Basically your patch tries to fix multiple thing at once. It should be better split.
For example, try the patch, and add 0d8c:0102 on that. Does it work?
Takashi
--- diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index be47d89..5a09621 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -2514,7 +2514,6 @@ static int parse_audio_format_rates(struct snd_usb_audio *chip, struct audioform * build the rate table and bitmap flags */ int r, idx; - unsigned int nonzero_rates = 0;
fp->rate_table = kmalloc(sizeof(int) * nr_rates, GFP_KERNEL); if (fp->rate_table == NULL) { @@ -2522,24 +2521,26 @@ static int parse_audio_format_rates(struct snd_usb_audio *chip, struct audioform return -1; }
- fp->nr_rates = nr_rates; - fp->rate_min = fp->rate_max = combine_triple(&fmt[8]); + fp->nr_rates = 0; + fp->rate_min = fp->rate_max = 0; for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) { unsigned int rate = combine_triple(&fmt[idx]); + if (!rate) + continue; /* C-Media CM6501 mislabels its 96 kHz altsetting */ if (rate == 48000 && nr_rates == 1 && chip->usb_id == USB_ID(0x0d8c, 0x0201) && fp->altsetting == 5 && fp->maxpacksize == 392) rate = 96000; - fp->rate_table[r] = rate; - nonzero_rates |= rate; - if (rate < fp->rate_min) + fp->rate_table[fp->nr_rates] = rate; + if (!fp->rate_min || rate < fp->rate_min) fp->rate_min = rate; - else if (rate > fp->rate_max) + if (!fp->rate_max || rate > fp->rate_max) fp->rate_max = rate; fp->rates |= snd_pcm_rate_to_rate_bit(rate); + fp->nr_rates++; } - if (!nonzero_rates) { + if (!fp->nr_rates) { hwc_debug("All rates were zero. Skipping format!\n"); return -1; }
Hello Takashi,
On 16 feb 2009, at 12:06, Takashi Iwai wrote:
The CM6207 incorrectly advertises its 96 kHz playback setting as 48 kHz in its USB device descriptor. This patch extends an existing workaround in usbaudio.c to also cover the CM6207.
Basically your patch tries to fix multiple thing at once. It should be better split.
Thanks for picking this up. Yes, I thought the min/max-rate fix was trivial enough to put in. I had no idea that you had something planned for it.
For example, try the patch, and add 0d8c:0102 on that. Does it work?
Yes, that works fine. Could you make it like that?
Greetings, Joris.
At Mon, 16 Feb 2009 20:05:17 +0100, Joris van Rantwijk wrote:
Hello Takashi,
On 16 feb 2009, at 12:06, Takashi Iwai wrote:
The CM6207 incorrectly advertises its 96 kHz playback setting as 48 kHz in its USB device descriptor. This patch extends an existing workaround in usbaudio.c to also cover the CM6207.
Basically your patch tries to fix multiple thing at once. It should be better split.
Thanks for picking this up. Yes, I thought the min/max-rate fix was trivial enough to put in. I had no idea that you had something planned for it.
For example, try the patch, and add 0d8c:0102 on that. Does it work?
Yes, that works fine. Could you make it like that?
Applied now with your fix. Thanks for a quick test!
Takashi
participants (2)
-
Joris van Rantwijk -
Takashi Iwai