kmssink on two spearate display

Matteo Valdina matteo.valdina at gmail.com
Thu Apr 5 03:06:07 UTC 2018


Thanks,

If I can pass the fd from the first pipeline to the second (in the same
process) should works?

>From the code, it doesn't look complicated.

Best
Matteo

On Wed, Apr 4, 2018 at 8:07 PM, Nicolas Dufresne <nicolas at ndufresne.ca>
wrote:

>
>
> Le mer. 4 avr. 2018 20:41, Matteo Valdina <matteo.valdina at gmail.com> a
> écrit :
>
>> Hi,
>> I'm trying to drive two separate display with kmssink (intel driver).
>>
>> I created two separate pipelines:
>>  pipeline 1 v4l2src device=/dev/video0 ! kmssink conncetor-id=63
>>  pipeline 1 v4l2src device=/dev/video0 ! kmssink conncetor-id=58
>>
>> My problem is that the second pipeline encounter and error on accessing
>> DRM resources.
>> So, I implemented a simple test application that runs the two pipelines
>> inside a single process.
>> Only the first pipeline works, the second encounters these error:
>>
>> 0:00:00.124567628  6195 0x7f31400028a0 ERROR                kmssink
>> gstkmssink.c:498:configure_mode_setting:<kmssink1> Failed to set mode:
>> Permission denied
>> 0:00:00.124603970  6195 0x7f31400028a0 WARN                 kmssink
>> gstkmssink.c:1058:gst_kms_sink_set_caps:<kmssink1> error: failed to
>> configure video mode
>>
>> I'm using GStreamer 1.14 and it using an i915.
>>
>> Can kmssink work concurrently run on two different display but the same
>> video card?
>>
>
> No, this would require the same FD being shared among kmssink, which is
> not implemented (or a cookie?). Obviously you could sudo it, but overall,
> kmssink need to be ported to atomic APIs to work smoothly.
>
>
>> Best
>> Matteo
>>
>>
>>
>>
>> --
>> “There are two ways of constructing a software design: One way is to make
>> it so simple that there are obviously no deficiencies, and the other way is
>> to make it so complicated that there are no obvious deficiencies. The first
>> method is far more difficult.”
>> - Tony Hoare
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>>
>
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>


-- 
“There are two ways of constructing a software design: One way is to make
it so simple that there are obviously no deficiencies, and the other way is
to make it so complicated that there are no obvious deficiencies. The first
method is far more difficult.”
- Tony Hoare
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