[PATCH AUTOSEL 5.4 191/350] ALSA: bebob: expand sleep just after breaking connections for protocol version 1

Sasha Levin
2019-12-10T21:10:53Z

From: Takashi Sakamoto <o-takashi@sakamocchi.jp>

[ Upstream commit d3eabe939aee3ffd5b133766a932629a9746298c ]

As long as I investigated, some devices with BeBoB protocol version 1
can be freezed during several hundreds milliseconds after breaking
connections. When accessing during the freezed time, any transaction
is corrupted. In the worst case, the device is going to reboot.

I can see this issue in:
* Roland FA-66
* M-Audio FireWire Solo

This commit expands sleep just after breaking connections to avoid
the freezed time as much as possible. I note that the freeze/reboot
behaviour is similar to below models:
* Focusrite Saffire Pro 10 I/O
* Focusrite Saffire Pro 26 I/O

The above models certainly reboot after breaking connections.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191101131323.17300-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/firewire/bebob/bebob_stream.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
index 6c1497d9f52ba..ce07ea0d4e71d 100644
--- a/sound/firewire/bebob/bebob_stream.c
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -415,15 +415,16 @@ static int make_both_connections(struct snd_bebob *bebob)
return 0;
}

-static void
-break_both_connections(struct snd_bebob *bebob)
+static void break_both_connections(struct snd_bebob *bebob)
{
cmp_connection_break(&bebob->in_conn);
cmp_connection_break(&bebob->out_conn);

- /* These models seems to be in transition state for a longer time. */
- if (bebob->maudio_special_quirk != NULL)
- msleep(200);
+ // These models seem to be in transition state for a longer time. When
+ // accessing in the state, any transactions is corrupted. In the worst
+ // case, the device is going to reboot.
+ if (bebob->version < 2)
+ msleep(600);
}

static int
--
2.20.1