kernel/git/stable/linux.git/sound/usb/clock.c, branch linux-3.9.y

ALSA: usb: Work around CM6631 sample rate change bug

2013-04-03T15:05:44+00:00

The C-Media CM6631 USB receiver doesn't respond to changes in sample rate while the interface is active. The same behavior is observed in other UAC2 hardware like the VIA VT1731. Reset the interface after setting the sampling frequency on sample rate changes, to ensure that the sample rate set by snd_usb_init_sample_rate() is used. Otherwise, the device will try to use the sample rate of the previous stream, causing distorted sound on sample rate changes. The reset is performed for all UAC2 devices, as it should not affect a standards compliant device, but it is only necessary for C-Media CM6631, VIA VT1731 and possibly others. Failure to read sample rate from the device is not handled as an error in set_sample_rate_v2(), as (permanent or intermittent) failure to read sample rate isn't essential for a successful sample rate set. Signed-off-by: Torstein Hegge Acked-by: Clemens Ladisch Signed-off-by: Takashi Iwai

ALSA: snd-usb: fix clock source validity index

2012-08-01T08:24:16+00:00

uac_clock_source_is_valid() uses the control selector value to access the bmControls bitmap of the clock source unit. This is wrong, as control selector values start from 1, while the bitmap uses all available bits. In other words, "Clock Validity Control" is stored in D3..2, not D5..4 of the clock selector unit's bmControls. Signed-off-by: Daniel Mack Reported-by: Andreas Koch Cc: stable@kernel.org Signed-off-by: Takashi Iwai

ALSA: usb-audio: increase control transfer timeout

2011-09-27T07:21:48+00:00

There are certain devices that are reportedly so slow that they need more than 100 ms to handle control transfers. Therefore, increase the timeout in mixer(_quirks).c to 1000 ms. The timeout parameter of snd_usb_ctl_msg() is now constant, so we can drop it. Reported-by: Felipe Balbi Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai

ALSA: usb-audio: assume valid clock

2011-05-18T09:44:44+00:00

If the interface can't report a clock's validity, assume that it's valid. Signed-off-by: Daniel Mack Reported-by: Vicente Joel Signed-off-by: Takashi Iwai

ALSA: usb-audio: fix detection of vendor-specific device protocol settings

2010-09-03T20:36:39+00:00

The Audio Class v2 support code in 2.6.35 added checks for the bInterfaceProtocol field. However, there are devices (usually those detected by vendor-specific quirks) that do not have one of the predefined values in this field, which made the driver reject them. To fix this regression, restore the old behaviour, i.e., assume that a device with an unknown bInterfaceProtocol field (other than UAC_VERSION_2) has more or less UAC-v1-compatible descriptors. [compile warning fixes by tiwai] Signed-off-by: Clemens Ladisch Cc: Daniel Mack Cc: Signed-off-by: Takashi Iwai

ALSA: usb-audio: silence a superfluous warning

2010-07-09T13:08:12+00:00

It is not advisable to print a warning when a device does not support setting the sample rate because this is perfectly valid for devices with a single rate or where rates are implicitly changed by selecting another alternate setting. Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai

ALSA: usb-audio: simplify control interface access

2010-06-23T14:10:23+00:00

As the control interface is now carried in struct snd_usb_audio, we can simplify the API a little and also drop the private ctrlif field from struct usb_mixer_interface. Also remove a left-over function prototype in pcm.h. Signed-off-by: Daniel Mack Signed-off-by: Takashi Iwai

ALSA: usb-audio: move and add some comments

2010-06-23T14:09:50+00:00

Also add a list of open topics. Signed-off-by: Daniel Mack Signed-off-by: Takashi Iwai

ALSA: usb-audio: clean up includes in clock.c

2010-06-23T14:09:14+00:00

Signed-off-by: Daniel Mack Signed-off-by: Takashi Iwai

ALSA: usb-audio: fix control messages for USB_RECIP_INTERFACE

2010-06-11T16:05:38+00:00

Control messages directed to an interface must have the interface number set in the lower 8 bits of wIndex. This wasn't done correctly for some clock and mixer messages. Signed-off-by: Daniel Mack Reported-by: Alex Lee Signed-off-by: Takashi Iwai