diff options
| author | Geoffrey D. Bennett <g@b4.vu> | 2025-07-28 19:00:35 +0930 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2025-07-28 11:42:39 +0200 |
| commit | 8a15ca0ca51399b652b1bbb23b590b220cf03d62 (patch) | |
| tree | bedcffabfbc48ad299ed097e9af231ca79229f06 | |
| parent | bd7814a4c0fd883894bdf9fe5eda24c9df826e4c (diff) | |
ALSA: scarlett2: Add retry on -EPROTO from scarlett2_usb_tx()
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>
| -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 49eeb1444dce..15bbdafc4894 100644 --- a/sound/usb/mixer_scarlett2.c +++ b/sound/usb/mixer_scarlett2.c @@ -2351,6 +2351,8 @@ 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); @@ -2374,10 +2376,15 @@ 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", |