opengl and drm on a pi 3b?

jc at jc at
Fri Mar 17 12:36:30 UTC 2017


>> Hi
>> As this isn't an "X" answer I've skipped the list.
> And I've put it back so its in the archive FFR.
>> What application
>> are you using?  Do you actually need X? do you actually need OpenGL?
> Yes on both counts. The app, linuxcnc, has a nice gui control interface
> which includes a backplot of the machines motions while its carving up a
> block of metal to make something.  Screen refresh rate with what I am
> getting is about 15 frames a second, just noticeably slow. The numbers
> in the digital readout of the cutter location in 3d space, should just
> roll by, but they jump a decade or more in displayed value if the
> machine is moving at 5 inches a minute now.
>> I ask these questions 'cos as it stands X + GL + HW Video is still a
>> bit unsupported on the Pi.  If you just want video then junk X & OGL
>> and your life will be a lot better.  X + HW decode can be made to work
>> just about acceptably but it takes some effort, add OGL into the mix
>> and whilst it should make life better by and large it doesn't (yet) as
>> the mmal stacks don't play nice with the GL stacks.
> Is there even movement afoot to fix this? If its fixed, the pi 3b can
> easily take over from the power hungry x86 boxes we generally use as the
> driving iron. Not an overnight takeover, but as the x86 boxes age out
> and people are becoming more conscious of the energy bills, it will
> happen.

Yes there is movement to fix this.  Eric is your friend in this regard. 
However having said that I don't anticipate your life getting magically
better when it is fixed as actually using the h/w to do the video decode
requires the app decoding the video to know about it.



>> Regards
>> JC
> Thanks John.
>> >Hello all, been a while since I rang your doorbell, greetings from
>> > West Virginia;
>> >
>> >I am in the process of converting an old lathe to cnc, and using a pi
>> > 3b as the driver.
>> >
>> >Doing some work on the configuration today, I got curious to see if
>> > the features I was adding to the configuration were pushing the poor
>> > pi to the point of exhaustion. Firing up htop, the various bits and
>> > pieces that together make up linuxcnc, were a total of about 4 or 5%
>> > of the cpu load.  Compton, the x compositor, was burning something
>> > in the region of 165%, or a little over 1.5 of its 4 cores. It was
>> > also a few megabytes into swap, so I rebooted it, after which
>> > compton was only using perhaps 35% of one core.
>> >
>> >But my main reason for posting is to see if any progress is being
>> > made on opengl and drm drivers for that bcm video the pi has.  The
>> > display is just slow enough to be noticeable.  The machine its
>> > driving can move at up to about 100 inches a minute, with bone
>> > breaking force, so it would be a definite safety advantage if the
>> > video could keep up with the machine in something resembling real
>> > time.
>> >
>> >So what, if any, is the status of faster video drivers for the pi's
>> > that use the bcm video?
>> >
>> >Thanks all.
>> >
>> >Cheers, Gene Heskett
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <>

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