On Sun, Feb 09, 2020 at 12:48:05PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 5.5-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From d51224b73d18d207912f15ad4eb7a4b456682729 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Date: Wed, 11 Dec 2019 12:47:57 +0100
Subject: [PATCH] media: cec: check 'transmit_in_progress', not 'transmitting'
Currently wait_event_interruptible_timeout is called in cec_thread_func()
when adap->transmitting is set. But if the adapter is unconfigured
while transmitting, then adap->transmitting is set to NULL. But the
hardware is still actually transmitting the message, and that's
indicated by adap->transmit_in_progress and we should wait until that
is finished or times out before transmitting new messages.
As the original commit says: adap->transmitting is the userspace view,
adap->transmit_in_progress reflects the hardware state.
However, if adap->transmitting is NULL and adap->transmit_in_progress
is true, then wait_event_interruptible is called (no timeout), which
can get stuck indefinitely if the CEC driver is flaky and never marks
the transmit-in-progress as 'done'.
So test against transmit_in_progress when deciding whether to use
the timeout variant or not, instead of testing against adap->transmitting.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Fixes: 32804fcb612b ("media: cec: keep track of outstanding transmits")
Cc: <stable@xxxxxxxxxxxxxxx> # for v4.19 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Duplicate commit:
ac479b51f3f4 ("media: cec: check 'transmit_in_progress', not 'transmitting'")
d51224b73d18 ("media: cec: check 'transmit_in_progress', not 'transmitting'")
--
Thanks,
Sasha
