Hans,
Can you apply this to v4l-utils?
Thanks!
Hans
>From 977eb253a3e7a5257a2051da240314e2dac385bf Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil@xxxxxxxxx>
Date: Sat, 13 Mar 2010 23:19:48 +0100
Subject: [PATCH] qv4l2: fix UVC support
The workaround for drivers using videobuf broke the UVC support.
Fix this.
Signed-off-by: Hans Verkuil <hverkuil@xxxxxxxxx>
---
utils/qv4l2-qt4/general-tab.cpp | 18 +++++++++++++++---
utils/qv4l2-qt4/qv4l2.cpp | 4 +++-
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/utils/qv4l2-qt4/general-tab.cpp b/utils/qv4l2-qt4/general-tab.cpp
index 50a3edc..706b15d 100644
--- a/utils/qv4l2-qt4/general-tab.cpp
+++ b/utils/qv4l2-qt4/general-tab.cpp
@@ -198,11 +198,23 @@ GeneralTab::GeneralTab(const QString &device, v4l2 &fd, int n, QWidget *parent)
if (m_querycap.capabilities & V4L2_CAP_STREAMING) {
v4l2_requestbuffers reqbuf;
- if (reqbufs_user_cap(reqbuf, 1))
+ // Yuck. The videobuf framework does not accept a count of 0.
+ // This is out-of-spec, but it means that the only way to test which
+ // method is supported is to give it a non-zero count. But non-videobuf
+ // drivers like uvc do not allow e.g. S_FMT calls after a REQBUFS call
+ // with non-zero counts unless there is a REQBUFS call with count == 0
+ // in between. This is actual proper behavior, although somewhat
+ // unexpected. So the only way at the moment to do this that works
+ // everywhere is to call REQBUFS with a count of 1, and then again with
+ // a count of 0.
+ if (reqbufs_user_cap(reqbuf, 1)) {
m_capMethods->addItem("User pointer I/O", QVariant(methodUser));
-
- if (reqbufs_mmap_cap(reqbuf, 1))
+ reqbufs_user_cap(reqbuf, 0);
+ }
+ if (reqbufs_mmap_cap(reqbuf, 1)) {
m_capMethods->addItem("Memory mapped I/O", QVariant(methodMmap));
+ reqbufs_mmap_cap(reqbuf, 0);
+ }
}
if (m_querycap.capabilities & V4L2_CAP_READWRITE) {
m_capMethods->addItem("read()", QVariant(methodRead));
diff --git a/utils/qv4l2-qt4/qv4l2.cpp b/utils/qv4l2-qt4/qv4l2.cpp
index 96cb4d7..63881be 100644
--- a/utils/qv4l2-qt4/qv4l2.cpp
+++ b/utils/qv4l2-qt4/qv4l2.cpp
@@ -352,7 +352,7 @@ void ApplicationWindow::stopCapture()
if (-1 == munmap(m_buffers[i].start, m_buffers[i].length))
perror("munmap");
// Free all buffers.
- reqbufs_mmap_out(reqbufs, 0);
+ reqbufs_mmap_cap(reqbufs, 0);
break;
case methodUser:
@@ -360,6 +360,8 @@ void ApplicationWindow::stopCapture()
perror("VIDIOC_STREAMOFF");
for (i = 0; i < m_nbuffers; ++i)
free(m_buffers[i].start);
+ // Free all buffers.
+ reqbufs_user_cap(reqbufs, 0);
break;
}
free(m_buffers);
--
1.6.4.2
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG
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