linux-toradex.git/sound/usb/endpoint.c, branch v3.14.37

ALSA: usb-audio: Fix races at disconnection and PCM closing

2014-07-07T01:57:29+00:00

commit 92a586bdc06de6629dae1b357dac221253f55ff8 upstream.

When a USB-audio device is disconnected while PCM is still running, we
still see some race: the disconnect callback calls
snd_usb_endpoint_free() that calls release_urbs() and then kfree()
while a PCM stream would be closed at the same time and calls
stop_endpoints() that leads to wait_clear_urbs().  That is, the EP
object might be deallocated while a PCM stream is syncing with
wait_clear_urbs() with the same EP.

Basically calling multiple wait_clear_urbs() would work fine, also
calling wait_clear_urbs() and release_urbs() would work, too, as
wait_clear_urbs() just reads some fields in ep.  The problem is the
succeeding kfree() in snd_pcm_endpoint_free().

This patch moves out the EP deallocation into the later point, the
destructor callback.  At this stage, all PCMs must have been already
closed, so it's safe to free the objects.

Reported-by: Alan Stern 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: usb-audio: work around corrupted TEAC UD-H01 feedback data

2014-06-07T17:28:16+00:00

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 
[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 
Reported-and-tested-by: Andrea Messa 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: usb: use multiple packets per urb for Wireless USB inbound audio

2013-11-27T10:55:13+00:00

For Wireless USB audio devices, use multiple isoc packets per URB for
inbound endpoints with a datainterval < 5.  This allows the WUSB host
controller to take advantage of bursting to service endpoints whose
logical polling interval is less than the 4ms minimum polling interval
limit in WUSB.

Signed-off-by: Thomas Pugliese 
Signed-off-by: Takashi Iwai

ALSA: usb-audio: remove unused endpoint flag EP_FLAG_ACTIVATED

2013-10-07T09:22:43+00:00

EP_FLAG_ACTIVATED is never tested for, remove it.

Signed-off-by: Eldad Zack 
Signed-off-by: Takashi Iwai

ALSA: usb-audio: rename alt_idx to altsetting

2013-10-07T09:22:03+00:00

As Clemens Ladisch kindly explained:
 "Please note that there are two methods to identify alternate settings:
  the number, which is the value in bAlternateSetting, and the index,
  which is the index in the descriptor array.  There might be some wording
  in the USB spec that these two values must be the same, but in reality,
  [insert standard rant about firmware writers], bAlternateSetting
  must be treated as a random ID value."

This patch changes the name to express the correct usage semantics.
No functional change.

Signed-off-by: Eldad Zack 
Signed-off-by: Takashi Iwai

ALSA: usb-audio: void return type of snd_usb_endpoint_deactivate()

2013-10-07T09:00:03+00:00

The return value of snd_usb_endpoint_deactivate() is not used,
make the function have no return value.
Update the documentation to reflect what the function is actually
doing.

Signed-off-by: Eldad Zack 
Signed-off-by: Takashi Iwai

ALSA: usb-audio: don't deactivate URBs on in-use EP

2013-10-07T08:55:14+00:00

If an endpoint in use, its associated URBs should not be
deactivated.

Signed-off-by: Eldad Zack 
Signed-off-by: Takashi Iwai

ALSA: usb-audio: remove unused parameter from sync_ep_set_params

2013-10-07T08:52:06+00:00

Since the format is not actually used in sync_ep_set_params(),
there is no need to pass it down.

Signed-off-by: Eldad Zack 
Signed-off-by: Takashi Iwai

ALSA: improve buffer size computations for USB PCM audio

2013-09-26T08:25:31+00:00

This patch changes the way URBs are allocated and their sizes are
determined for PCM playback in the snd-usb-audio driver.  Currently
the driver allocates too few URBs for endpoints that don't use
implicit sync, making underruns more likely to occur.  This may be a
holdover from before I/O delays could be measured accurately; in any
case, it is no longer necessary.

The patch allocates as many URBs as possible, subject to four
limitations:

	The total number of URBs for the endpoint is not allowed to
	exceed MAX_URBS (which the patch increases from 8 to 12).

	The total number of packets per URB is not allowed to exceed
	MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is
	decreased from 20 to 6.

	The total duration of queued data is not allowed to exceed
	MAX_QUEUE, which is decreased from 24 ms to 18 ms.

	The total number of ALSA frames in the output queue is not
	allowed to exceed the ALSA buffer size.

The last requirement is the hardest to implement.  Currently the
number of URBs needed to fill a buffer cannot be determined in
advance, because a buffer contains a fixed number of frames whereas
the number of frames in an URB varies to match shifts in the device's
clock rate.  To solve this problem, the patch changes the logic for
deciding how many packets an URB should contain.  Rather than using as
many as possible without exceeding an ALSA period boundary, now the
driver uses only as many packets as needed to transfer a predetermined
number of frames.  As a result, unless the device's clock has an
exceedingly variable rate, the number of URBs making up each period
(and hence each buffer) will remain constant.

The overall effect of the patch is that playback works better in
low-latency settings.  The user can still specify values for
frames/period and periods/buffer that exceed the capabilities of the
hardware, of course.  But for values that are within those
capabilities, the performance will be improved.  For example, testing
shows that a high-speed device can handle 32 frames/period and 3
periods/buffer at 48 KHz, whereas the current driver starts to get
glitchy at 64 frames/period and 2 periods/buffer.

A side effect of these changes is that the "nrpacks" module parameter
is no longer used.  The patch removes it.

Signed-off-by: Alan Stern 
CC: Clemens Ladisch 
Tested-by: Daniel Mack 
Tested-by: Eldad Zack 
Signed-off-by: Takashi Iwai

Merge tag 'asoc-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-next

2013-08-23T12:12:22+00:00

ASoC: Updates for v3.12

- DAPM is now mandatory for CODEC drivers in order to avoid the repeated
  regressions in the special cases for non-DAPM CODECs and make it
  easier to integrate with other components on boards.  All existing
  drivers have had some level of DAPM support added.
- A lot of cleanups in DAPM plus support for maintaining controls in a
  specific state while a DAPM widget all contributed by Lars-Peter Clausen.
- Core helpers for bitbanged AC'97 reset from Markus Pargmann.
- New drivers and support for Analog Devices ADAU1702 and ADAU1401(a),
  Asahi Kasei Microdevices AK4554, Atmel AT91ASM9x5 and WM8904 based
  machines, Freescale S/PDIF and SSI AC'97, Renesas R-Car SoCs, Samsung
  Exynos5420 SoCs, Texas Instruments PCM1681 and PCM1792A and Wolfson
  Microelectronics WM8997.
- Support for building drivers that can support it cross-platform for
  compile test.