From: Marcel Holtmann marcel@holtmann.org
[ Upstream commit 9f3b61dc1dd7b81e99e7ed23776bb64a35f39e1a ]
When polling a connected /dev/hidrawX device, it is useful to get the EPOLLOUT when writing is possible. Since writing is possible as soon as the device is connected, always return it.
Right now EPOLLOUT is only returned when there are also input reports are available. This works if devices start sending reports when connected, but some HID devices might need an output report first before sending any input reports. This change will allow using EPOLLOUT here as well.
Fixes: 378b80370aa1 ("hidraw: Return EPOLLOUT from hidraw_poll") Signed-off-by: Marcel Holtmann marcel@holtmann.org Cc: stable@vger.kernel.org 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 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index c75b66d..a025b69 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -260,10 +260,10 @@ 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 | EPOLLOUT; + return EPOLLIN | EPOLLRDNORM; if (!list->hidraw->exist) return EPOLLERR | EPOLLHUP; - return 0; + return EPOLLOUT | EPOLLWRNORM; }
static int hidraw_open(struct inode *inode, struct file *file)