From: Fabian Henneke <fabian.henneke@gmail.com> [ Upstream commit 378b80370aa1fe50f9c48a3ac8af3e416e73b89f ] Always return EPOLLOUT from hidraw_poll when a device is connected. This is safe since writes are always possible (but will always block). hidraw does not support non-blocking writes and instead always calls blocking backend functions on write requests. Hence, so far, a call to poll never returned EPOLLOUT, which confuses tools like socat. Signed-off-by: Fabian Henneke <fabian.henneke@gmail.com> In-reply-to: <CA+hv5qkyis03CgYTWeWX9cr0my-d2Oe+aZo+mjmWRXgjrGqyrw@mail.gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/hid/hidraw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index c7cff92..c75b66d 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -260,7 +260,7 @@ static __poll_t hidraw_poll(struct file *file, poll_table *wait) poll_wait(file, &list->hidraw->wait, wait); if (list->head != list->tail) - return EPOLLIN | EPOLLRDNORM; + return EPOLLIN | EPOLLRDNORM | EPOLLOUT; if (!list->hidraw->exist) return EPOLLERR | EPOLLHUP; return 0; -- 1.8.3