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Re: screenblanker vs login

On Thursday 15 February 2018 01:05:52 Stefan Monnier wrote:

> > This still looks like a 1 man part time effort. And it will likely
> > remain so until there is arm64 support in debian.  But likely next
> > generation after stretch now.
> Mali support is unrelated to Debian.  The main issue is that ARM (the
> company behind the Mali GPUs) works hard to undermine any effort at
> such Free Software drivers (it's much worse than just withholding
> information, since the key info has already been reverse engineered
> anyway).
Do they not understand that the market for their hardware would expand 
considerably if they'd supply the info and encourage our FSF aligned 
people to write the drivers,?

Look at the nouveau situtation. We have a driver that drives nvidia's 
hardware at quite reasonable speeds, and which CAN be used in the 
presence of a realtime kernel without doing too much damage to that 
kernels performance, unlike the nvidia driver, which totally destroys 
any semblance of realtime by locking out interrupts for hundreds of 
milliseconds at a time.

I'd call that driver a rather resounding success story for free software.

> Other relevant information is that Mali is really just the GPU,
> i.e. a processor that can perform efficient computations like those
> used for 3D rendering.  This is separate from the display engine
> itself (the thing that takes a framebuffer and pushes the pixels to a
> screen), or from the video encode/decode hardware.

And the framebuffer is both slow, and in the case of the pi, limited 
color depth, 5,6,5 I think as opposed to the full 8,8,8. The pi3b 
manages about 7 frames a second for a refresh rate running jessie and 
lxde. That does NOT give us a backplot thats in time with what the 
machine is doing. And that can be dangerous to both the machine and the 
operator if he gets in its way. But I do get the impression the 
framebuffer of a rock64 is some faster. Color depth I haven't checked
other than to note that synaptic, with its plethora of shades of white, 
is considerable more usable on a rock64 running stretch + xfce, than it 
is on the pi running lxde.

> So for example on Allwinner (sunxi) hardware there's recent progress
> on getting support for the display engine (some of it already in
> mainline Linux) and the video decoder (work still in progress).

Having built the v4.14.15-rt13 kernel on the rock64, that has not or is 
not shown in the "make menuconfig" options when the arch is set for 
rockchip. At least not that I have tripped over.

However, I just checked the modules.builtin file in the built kernel tree 
and found this entry: kernel/drivers/gpu/drm/arm/mali-dp.ko but I've not 
a clue what it can do, primarily because there is not a ready recipe as 
to how to go about changing the kernel in a u-boot install.  If anyone 
has that recipe, please share.

I also note from reading that file, that I am far from finished at 
stripping it down, its still building all the dvb stuffs. And that I 
need to get a fan on it, it doesn't survive a make -j4. I do have a fan 
on the pi, and its rock solid.
pi@picnc:~ $ uptime
 08:00:52 up 39 days, 12:18,  3 users,  load average: 0.11, 0.19, 0.22

Thank you,  Stefan

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 <http://geneslinuxbox.net:6309/gene>

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