ALSA: firewire-motu: drop EPOLLOUT from poll return values as write is not supported

Browse source

[ Upstream commit aea3493246 ]

The ALSA HwDep character device of the firewire-motu driver incorrectly
returns EPOLLOUT in poll(2), even though the driver implements no operation
for write(2). This misleads userspace applications to believe write() is
allowed, potentially resulting in unnecessarily wakeups.

This issue dates back to the driver's initial code added by a commit
71c3797779 ("ALSA: firewire-motu: add hwdep interface"), and persisted
when POLLOUT was updated to EPOLLOUT by a commit a9a08845e9 ('vfs: do
bulk POLL* -> EPOLL* replacement("").').

This commit fixes the bug.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://patch.msgid.link/20250829233749.366222-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Takashi Sakamoto 2025-08-30 08:37:49 +09:00 • committed by Greg Kroah-Hartman

parent 363a599da6

commit 7d2897fa48

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

sound/firewire/motu/motu-hwdep.c

View file