diff mbox series

[PATCHv3,7/7] cec: add EPOLLPRI in poll() when dev is unregistered

Message ID 20201201124446.448595-8-hverkuil-cisco@xs4all.nl
State Accepted
Commit 4f20b7beca5a183139b22ed4fdfc161396452426
Headers show
Series media: poll fixes | expand

Commit Message

Hans Verkuil Dec. 1, 2020, 12:44 p.m. UTC
If the CEC device was unregistered, then add EPOLLPRI to
the poll() mask. Otherwise a select() that only waits for
exceptions will not wake up. A select() that waits for
read and/or write events *will* wake up on an EPOLLERR, but
not (for some reason) if it just waits for exceptions.

Strangly the epoll functionality will wakeup on EPOLLERR if
you just wait for an exception, so in this respect select()
and epoll differ.

In the end it doesn't really matter, what matters is that
polling file handles are woken up on device unregistration.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/cec/core/cec-api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index f922a2196b2b..769e6b4cddce 100644
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -40,7 +40,7 @@  static __poll_t cec_poll(struct file *filp,
 
 	poll_wait(filp, &fh->wait, poll);
 	if (!cec_is_registered(adap))
-		return EPOLLERR | EPOLLHUP;
+		return EPOLLERR | EPOLLHUP | EPOLLPRI;
 	mutex_lock(&adap->lock);
 	if (adap->is_configured &&
 	    adap->transmit_queue_sz < CEC_MAX_MSG_TX_QUEUE_SZ)