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| author | Geoffrey D. Bennett <g@b4.vu> | 2025-07-28 19:00:35 +0930 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-15 12:14:12 +0200 |
| commit | e1c508818cba27c0ef44dd0f3ee487c205eb6abd (patch) | |
| tree | b37ab8a19a0e27d6a3ec9b72b52384019e12dc0b | |
| parent | 0f158abad0ce0a1e7df0b420b6e6afba91179183 (diff) | |
| download | linux-e1c508818cba27c0ef44dd0f3ee487c205eb6abd.tar.gz linux-e1c508818cba27c0ef44dd0f3ee487c205eb6abd.tar.bz2 linux-e1c508818cba27c0ef44dd0f3ee487c205eb6abd.zip | |
ALSA: scarlett2: Add retry on -EPROTO from scarlett2_usb_tx()
commit 8a15ca0ca51399b652b1bbb23b590b220cf03d62 upstream.
During communication with Focusrite Scarlett Gen 2/3/4 USB audio
interfaces, -EPROTO is sometimes returned from scarlett2_usb_tx(),
snd_usb_ctl_msg() which can cause initialisation and control
operations to fail intermittently.
This patch adds up to 5 retries in scarlett2_usb(), with a delay
starting at 5ms and doubling each time. This follows the same approach
as the fix for usb_set_interface() in endpoint.c (commit f406005e162b
("ALSA: usb-audio: Add retry on -EPROTO from usb_set_interface()")),
which resolved similar -EPROTO issues during device initialisation,
and is the same approach as in fcp.c:fcp_usb().
Fixes: 9e4d5c1be21f ("ALSA: usb-audio: Scarlett Gen 2 mixer interface")
Closes: https://github.com/geoffreybennett/linux-fcp/issues/41
Cc: stable@vger.kernel.org
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://patch.msgid.link/aIdDO6ld50WQwNim@m.b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/usb/mixer_scarlett2.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c index 4cddf84db631..8e91fce6274f 100644 --- a/sound/usb/mixer_scarlett2.c +++ b/sound/usb/mixer_scarlett2.c @@ -2329,6 +2329,8 @@ static int scarlett2_usb( struct scarlett2_usb_packet *req, *resp = NULL; size_t req_buf_size = struct_size(req, data, req_size); size_t resp_buf_size = struct_size(resp, data, resp_size); + int retries = 0; + const int max_retries = 5; int err; req = kmalloc(req_buf_size, GFP_KERNEL); @@ -2352,10 +2354,15 @@ static int scarlett2_usb( if (req_size) memcpy(req->data, req_data, req_size); +retry: err = scarlett2_usb_tx(dev, private->bInterfaceNumber, req, req_buf_size); if (err != req_buf_size) { + if (err == -EPROTO && ++retries <= max_retries) { + msleep(5 * (1 << (retries - 1))); + goto retry; + } usb_audio_err( mixer->chip, "%s USB request result cmd %x was %d\n", |