opengl and drm on a pi 3b?

Gene Heskett gheskett at
Fri Mar 17 00:13:28 UTC 2017

On Thursday 16 March 2017 14:18:53 you wrote:

> 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 
> 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."
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