From eaa1b01fe709d6a236a9cec74813e0400601fd23 Mon Sep 17 00:00:00 2001
From: Alexander Tsoy <alexander@tsoy.me>
Date: Thu, 1 Feb 2024 14:53:08 +0300
Subject: [PATCH] ALSA: usb-audio: Ignore clock selector errors for single connection
Git-commit: eaa1b01fe709d6a236a9cec74813e0400601fd23
Patch-mainline: v6.8-rc3
References: git-fixes
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>
---
sound/usb/clock.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -328,8 +328,16 @@ static int __uac_clock_find_source(struc
if (chip->quirk_flags & QUIRK_FLAG_SKIP_CLOCK_SELECTOR)
return ret;
err = uac_clock_selector_set_val(chip, entity_id, cur);
- if (err < 0)
+ if (err < 0) {
+ if (pins == 1) {
+ usb_audio_dbg(chip,
+ "%s(): selector returned an error, "
+ "assuming a firmware bug, id %d, ret %d\n",
+ __func__, clock_id, err);
+ return ret;
+ }
return err;
+ }
}
if (!validate || ret > 0 || !chip->autoclock)