[alsa-devel] [RESENT] [PATCH - Fix Fast Track Ultra series: 44.1/88.1 kHz 1/Fix playback/capture issues and related chrashes at 44100 Hz and 88200 Hz for M-Audio Fast Track Ultra series.
fexpop at web.de
Wed Sep 1 10:48:54 CEST 2010
This is my second try to get support for all supported sample rates for
the Fast Track Ultra (FTU) series into mainline alsa.
For clarification: Current Alsa already recognizes the supported sample
rates. But it will sound very corrupted at 44.1000 Hz and 88.200 Hz.
Without this patch your system will even probably freeze eventually when
using the FTU at 44.100/88.200 Hz too long.
So the key idea in this patch is not to get 44.1 kHz and 88.2 kHz listed
as supported sample rates (as they already are recognized) but to change
the endpoint attributes.
Citing dhubsith on the M-Audio forum:
" The problem with using QUIRK_AUDIO_STANDARD_INTERFACE rather than
QUIRK_AUDIO_FIXED_ENDPOINT is that ep_attr does not get set correctly.
The device default for synchronization is async (0x05) for both capture
and playback, but in fact it should be set to adaptive (0x09) on
playback, so that playback follows capture, this way you don't get
capture and playback using different sample rates.
Also, the Interface Class protocol for the device defaults to Vendor
Specific Class, but the driver only recognizes Class 1 or 2. The device
is really Class 1, so we have to force it to reflect this. There are 4
places that we need to set this."
The patch has been discussed starting here:
The "key" has been found by dhubsith. Please read posts #79, #81, #84,
In post #102 of that forum you can even find an alternate patch by
dhubsith which doesn't use a fixed endpoint quirk but sets
protocol = UAC_VERSION_1;
for the FTU devices in sound/usb/format .c. You might even consider that
patch. (I've resend it to alsa-devel yesterday).
After all, either one of the above mentioned patches should go into
alsa, as right now we can't use the FTU devices at 44.1 and 88.2 kHz.
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 0 bytes
Desc: not available
Url : http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20100901/dbc7e90b/attachment.patch
More information about the Alsa-devel