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authorDave Airlie <airlied@redhat.com>2016-02-25 10:30:59 +1000
committerDave Airlie <airlied@redhat.com>2016-02-25 10:30:59 +1000
commit0041ee4d3642f9ad80a479fbe51a4bc7f3cd8294 (patch)
tree84434b300002445bbf170bebee148cc719cf7829 /Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml
parentd2eaa59000c7717e68a75cf2c106f056d2bc30b4 (diff)
parent7863ac504bc5473eb99c4356120aa372d453143e (diff)
Merge branch 'drm/next/du' of git://linuxtv.org/pinchartl/fbdev into drm-next
rcar-du updates. * 'drm/next/du' of git://linuxtv.org/pinchartl/fbdev: (281 commits) drm: rcar-du: Add tri-planar memory formats support drm: rcar-du: Add probe deferral debug messages drm: rcar-du: lvds: Add R-Car Gen3 support drm: rcar-du: lvds: Rename PLLEN bit to PLLON drm: rcar-du: lvds: Fix PLL frequency-related configuration drm: rcar-du: lvds: Avoid duplication of clock clamp code drm: rcar-du: Add R8A7795 device support drm: rcar-du: Output the DISP signal on the ODDF pin drm: rcar-du: Output the DISP signal on the DISP pin drm: rcar-du: Support up to 4 CRTCs drm: rcar-du: Drop LVDS double dependency on OF drm: rcar-du: Enable compilation on ARM64 drm: rcar-du: Fix compile warning on 64-bit platforms drm: rcar-du: Expose the VSP1 compositor through KMS planes drm: rcar-du: Move plane allocator to rcar_du_plane.c drm: rcar-du: Restart the DU group when a plane source changes drm: rcar-du: Add VSP1 compositor support drm: rcar-du: Add VSP1 support to the planes allocator drm: rcar-du: Refactor plane setup drm: rcar-du: Compute plane DDCR4 register value directly ...
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml')
-rw-r--r--Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml14
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml
index e9c70a8f3476..0c93677d16b4 100644
--- a/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml
@@ -60,9 +60,19 @@ input</refpurpose>
automatically, similar to sensing the video standard. To do so, applications
call <constant>VIDIOC_QUERY_DV_TIMINGS</constant> with a pointer to a
&v4l2-dv-timings;. Once the hardware detects the timings, it will fill in the
-timings structure.
+timings structure.</para>
-If the timings could not be detected because there was no signal, then
+<para>Please note that drivers shall <emphasis>not</emphasis> switch timings automatically
+if new timings are detected. Instead, drivers should send the
+<constant>V4L2_EVENT_SOURCE_CHANGE</constant> event (if they support this) and expect
+that userspace will take action by calling <constant>VIDIOC_QUERY_DV_TIMINGS</constant>.
+The reason is that new timings usually mean different buffer sizes as well, and you
+cannot change buffer sizes on the fly. In general, applications that receive the
+Source Change event will have to call <constant>VIDIOC_QUERY_DV_TIMINGS</constant>,
+and if the detected timings are valid they will have to stop streaming, set the new
+timings, allocate new buffers and start streaming again.</para>
+
+<para>If the timings could not be detected because there was no signal, then
<errorcode>ENOLINK</errorcode> is returned. If a signal was detected, but
it was unstable and the receiver could not lock to the signal, then
<errorcode>ENOLCK</errorcode> is returned. If the receiver could lock to the signal,