From 8648e95e3aa1a3d01423a98b5234192c811fc4bf Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Wed, 4 Dec 2019 03:37:13 +0100 Subject: [PATCH] HID: hidraw: Fix returning EPOLLOUT from hidraw_poll commit 9f3b61dc1dd7b81e99e7ed23776bb64a35f39e1a upstream. 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 Signed-off-by: Jiri Kosina [bwh: Backported to 3.16: s/EPOLL/POLL/g] Signed-off-by: Ben Hutchings --- 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 27d2f5a48a11c..e60d9c88bd35e 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -265,10 +265,10 @@ static unsigned int hidraw_poll(struct file *file, poll_table *wait) poll_wait(file, &list->hidraw->wait, wait); if (list->head != list->tail) - return POLLIN | POLLRDNORM | POLLOUT; + return POLLIN | POLLRDNORM; if (!list->hidraw->exist) return POLLERR | POLLHUP; - return 0; + return POLLOUT | POLLWRNORM; } static int hidraw_open(struct inode *inode, struct file *file) -- 2.47.2