[mythtv-commits] Ticket #12522: v4l2 recorders incorrectly call VIDIOC_STREAMON when not using streaming mode

MythTV noreply at mythtv.org
Wed Oct 7 16:17:09 UTC 2015


#12522: v4l2 recorders incorrectly call VIDIOC_STREAMON when not using streaming
mode
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 Reporter:  stuarta               |          Owner:  stuarta
     Type:  Bug Report - General  |         Status:  new
 Priority:  minor                 |      Milestone:  0.27.6
Component:  MythTV - General      |        Version:  0.27.5
 Severity:  medium                |     Resolution:
 Keywords:                        |  Ticket locked:  0
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Comment (by stuarta):

 So some further analysis yields that this is a bit deeper.

 Previous tickets #9825, #10519 and #12336 have added code
 to forcefully remove the streaming capability from MythTV's
 view of the device.

 The real problem is that we are blindly calling either
 VIDIOC_STREAMON or VIDIOC_STREAMOFF when we aren't even using
 the device in streaming mode.

 Some of the drivers will allow a STREAMOFF even when the device
 isn't setup for streaming, others will throw "Invalid argument"
 when trying to disable streaming when it's not active.

 When the driver allows STREAMOFF, it will normally fail with
 an "Invalid argument" to the VIDIOC_STREAMON ioctl, because
 we never setup the require buffers in the v4lrecorder to use
 that mode.

 See the V4L2 API: http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-
 streamon.html

--
Ticket URL: <https://code.mythtv.org/trac/ticket/12522#comment:1>
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