From acf92046a0a666051f9c6b4a53d874c618203173 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hans.verkuil@cisco.com>
Date: Sat, 20 Sep 2014 16:16:36 -0300
Subject: [PATCH] [media] DocBook media: fix the poll() 'no QBUF' documentation
Clarify what poll() returns if STREAMON was called but not QBUF.
Make explicit the different behavior for this scenario for
capture and output devices.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
---
Documentation/DocBook/media/v4l/func-poll.xml | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/func-poll.xml b/Documentation/DocBook/media/v4l/func-poll.xml
index 85cad8bff5ba7..bd07104a35e95 100644
--- a/Documentation/DocBook/media/v4l/func-poll.xml
+++ b/Documentation/DocBook/media/v4l/func-poll.xml
@@ -44,10 +44,18 @@ Capture devices set the <constant>POLLIN</constant> and
flags. When the function timed out it returns a value of zero, on
failure it returns <returnvalue>-1</returnvalue> and the
<varname>errno</varname> variable is set appropriately. When the
-application did not call &VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the
+application did not call &VIDIOC-STREAMON; the
<function>poll()</function> function succeeds, but sets the
<constant>POLLERR</constant> flag in the
-<structfield>revents</structfield> field.</para>
+<structfield>revents</structfield> field. When the
+application has called &VIDIOC-STREAMON; for a capture device but hasn't
+yet called &VIDIOC-QBUF;, the <function>poll()</function> function
+succeeds and sets the <constant>POLLERR</constant> flag in the
+<structfield>revents</structfield> field. For output devices this
+same situation will cause <function>poll()</function> to succeed
+as well, but it sets the <constant>POLLOUT</constant> and
+<constant>POLLWRNORM</constant> flags in the <structfield>revents</structfield>
+field.</para>
<para>When use of the <function>read()</function> function has
been negotiated and the driver does not capture yet, the