For devices with multiple clock sources connected to a selector, we need
to check what a clock selector control request has returned. This is
needed to ensure that a requested clock source is indeed selected and for
autoclock feature to work.

For devices with single clock source connected, if we get an error there
is nothing else we can do about it. We can't skip clock selector setup as
it is required by some devices. So lets just ignore error in this case.

This should fix various buggy Mackie devices:

[  649.109785] usb 1-1.3: parse_audio_format_rates_v2v3(): unable to find clock source (clock -32)
[  649.111946] usb 1-1.3: parse_audio_format_rates_v2v3(): unable to find clock source (clock -32)
[  649.113822] usb 1-1.3: parse_audio_format_rates_v2v3(): unable to find clock source (clock -32)

There is also interesting info from the Windows documentation [1] (this
is probably why manufacturers dont't even test this feature):

"The USB Audio 2.0 driver doesn't support clock selection. The driver
uses the Clock Source Entity, which is selected by default and never
issues a Clock Selector Control SET CUR request."

Link: https://learn.microsoft.com/en-us/windows-hardware/drivers/audio/usb-2-0-audio-drivers [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217314
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218175
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218342
Signed-off-by: Alexander Tsoy <alexander@tsoy.me>
Link: https://lore.kernel.org/r/20240201115308.17838-1-alexander@tsoy.me
Signed-off-by: Takashi Iwai <tiwai@suse.de>

This reverts commit 67794f882adca00d043899ac248bc002751da9f6.

We need to explicitly set up the clock selector to workaround a problem
with the Behringer mixers. This was originally done in d2e8f641257d
("ALSA: usb-audio: Explicitly set up the clock selector")

The problem with MOTU M Series mentioned in commit message was fixed in
a different way by checking control capabilities of clock selectors.

Signed-off-by: Alexander Tsoy <alexander@tsoy.me>
Link: https://lore.kernel.org/r/20240128132338.819273-1-alexander@tsoy.me
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Clock selector control might be read-only. Add corresponding checks
to prevent sending control requests that would fail.

Signed-off-by: Alexander Tsoy <alexander@tsoy.me>
Link: https://lore.kernel.org/r/20240125205457.28258-1-alexander@tsoy.me
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Since commit 086b957cc17f5 ("ALSA: usb-audio: Skip the clock selector
inquiry for single connections") we are already skipping clock selector
inquiry if only one clock source is connected, but we are still sending
a set request. Lets skip that too.

This should fix errors when setting a sample rate on devices that don't
have any controls present within the clock selector. An example of such
device is the new revision of MOTU M Series (07fd:000b):

      AudioControl Interface Descriptor:
        bLength                 8
        bDescriptorType        36
        bDescriptorSubtype     11 (CLOCK_SELECTOR)
        bClockID                1
        bNrInPins               1
        baCSourceID(0)          2
        bmControls           0x00
        iClockSelector          0

Perhaps we also should check if clock selectors are readable and writeable
like we already do for clock sources, but this is out of scope of this
patch.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217601
Signed-off-by: Alexander Tsoy <alexander@tsoy.me>
Link: https://lore.kernel.org/r/20240123134635.54026-1-alexander@tsoy.me
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Maris found out that the quirk for TEAC devices to work around the
clock setup is needed to apply only when the base clock is changed,
e.g. from 48000-based clocks (48000, 96000, 192000, 384000) to
44100-based clocks (44100, 88200, 176400, 352800), or vice versa,
while switching to another clock with the same base clock doesn't need
the (forcible) interface setup.

This patch implements the optimization for the TEAC clock quirk to
avoid the unnecessary interface re-setup.

Fixes: 5ce0b06ae5e6 ("ALSA: usb-audio: Workaround for clock setup on TEAC devices")
Reported-by: Maris Abele <maris7abele@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220531130749.30357-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Maris reported that TEAC UD-501 (0644:8043) doesn't work with the
typical "clock source 41 is not valid, cannot use" errors on the
recent kernels.  The currently known workaround so far is to restore
(partially) what we've done unconditionally at the clock setup;
namely, re-setup the USB interface immediately after the clock is
changed.  This patch re-introduces the behavior conditionally for TEAC
devices.

Further notes:
- The USB interface shall be set later in
  snd_usb_endpoint_configure(), but this seems to be too late.
- Even calling  usb_set_interface() right after
  sne_usb_init_sample_rate() doesn't help; so this must be related
  with the clock validation, too.
- The device may still spew the "clock source 41 is not valid" error
  at the first clock setup.  This seems happening at the very first
  try of clock setup, but it disappears at later attempts.
  The error is likely harmless because the driver retries the clock
  setup (such an error is more or less expected on some devices).

Fixes: bf6313a0ff76 ("ALSA: usb-audio: Refactor endpoint management")
Reported-and-tested-by: Maris Abele <maris7abele@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220521064627.29292-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

The pointer cs_desc return from snd_usb_find_clock_source could
be null, so there is a potential null pointer dereference issue.
Fix this by adding a null check before dereference.

Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk>
Link: https://lore.kernel.org/r/20211024111736.11342-1-cyeaa@connect.ust.hk
Signed-off-by: Takashi Iwai <tiwai@suse.de>

snd_usb_find_clock_source and snd_usb_find_clock_selector are helper
macros that look at an entity id and validate that this entity id is
in fact a clock source or a clock selector. The present comments
inside __uac_clock_find_source give the reader the impression we're
looking for an entity id.

We're looking for an entity id indeed, the clock source, but since
__uac_clock_find_source is recursive, we're also looking *at* the
entity ids, in the search for the one clock source.

Fix the comment so we don't give readers a wrong idea.

Signed-off-by: Geraldo Nascimento <geraldogabriel@gmail.com>
Link: https://lore.kernel.org/r/YU6Kj05oOqRmhJDf@geday
Signed-off-by: Takashi Iwai <tiwai@suse.de>

There are a couple of device-specific quirks in the clock setup code,
and those can be moved gracefully to quirk_flags, too.

Link: https://lore.kernel.org/r/20210729073855.19043-7-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

As more and more device-specific workarounds came up and gathered in
various places, it becomes harder to manage.  Now it's time to clean
up and collect workarounds more consistently and make them more easily
applicable.

This patch is the first step for that: a new field quirk_flags is
introduced in snd_usb_audio struct to contain the bit flags for
various device-specific quirks.  Those are separate one from the
quirks in quirks-table.h; the quirks-table.h entries are for more
intrusive stuff that needs the descriptor override, while the new
quirk_flags is for easier ones that are tied with the vendor:product
IDs.

In this patch, as the first example, we convert the list of devices
and vendors to ignore GET_SAMPLE_RATE, formerly defined in
snb_usb_get_sample_rate_quirk().

Link: https://lore.kernel.org/r/20210729073855.19043-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>