On Thu, 4 Apr 2019 17:38:15 -0400
Gene Heskett <gheskett@...> wrote:

> On Thursday 04 April 2019 17:16:04 E. Liddell wrote:
> 
> > On Thu, 4 Apr 2019 08:01:11 -0400
> >
> > Gene Heskett <gheskett@...> wrote:
> > > Actually. jessie on the pi wasn't too bad. I am
> > > actually getting things done with it. But info on the wintel stuff
> > > is common knowledge. Want to replace the armhf (pi) or arm64
> > > (rock64) kernel with a realtime version?  Nobody else sees the need,
> > > so your questions get ignored, not answered by the people who do
> > > have it all figured out.  Thats BS.
> >
> > For the pi, shouldn't it just be a matter of following your distro's
> > build-your- own-kernel instructions, using the pi-specific kernel
> > sources and base config, and applying the rt patchset on top?
> 
> No clue, I built it for the rock64, on the rock64, useing the patches 
> from the linux-rt mailing list links, but when I asked how to install 
> it, 3 times  over about as many weeks, and got ignored, I gave up. Their 
> propaganda says good support, but AFAIWC, there isn't any.  But the pi 
> is only very marginally better.  Bulding an rt kernel on the pi is a 
> several hour project, on the rock64 its about 30 minutes, which amply 
> demo's the difference in speeds.  Too bad I cannot use it. Neither has 
> any docs available to aid the hacker. Those are proprietary designs.  
> Run the linux they supply, or go pound sand.

The pi is quite well-documented, except for the internals of a couple of 
hardware blobs.  The rock64 . . . a quick search suggests much less 
documentation is available, and the detailed tech-spec stuff seems to be in 
Chinese, which is no help.  Scour /boot for the existing kernel, that's all I 
can advise--it should be in there somewhere.

If you're still interested in setting up the pi, it expects to find the kernel 
with a fixed filename in the boot partition.  It also needs some auxiliary 
files in there.

Here's what the boot section of the Gentoo image I assembled for my
pi3 looks like:

ryu ~ # ls -l /mnt/data/armchroot/boot/
total 16376
-rw-r--r-- 1 root root   15992 Dec  6 19:22 bcm2710-rpi-3-b.dtb
-rw-r--r-- 1 root root   50268 Dec  6 19:22 bootcode.bin
-rw-r--r-- 1 root root      48 Dec  6 20:42 cmdline.txt
-rw-r--r-- 1 root root    2527 Dec  6 19:22 fixup_cd.dat
-rw-r--r-- 1 root root    6635 Dec  6 19:22 fixup.dat
-rw-r--r-- 1 root root    9770 Dec  6 19:22 fixup_db.dat
-rw-r--r-- 1 root root    9768 Dec  6 19:22 fixup_x.dat
-rw-r--r-- 1 root root 4233216 Dec  6 19:09 kernel7.img
drwxr-xr-x 2 root root    4096 Dec  6 19:22 overlays
-rw-r--r-- 1 root root  641252 Dec  6 19:22 start_cd.elf
-rw-r--r-- 1 root root 4974116 Dec  6 19:22 start_db.elf
-rw-r--r-- 1 root root 2840612 Dec  6 19:22 start.elf
-rw-r--r-- 1 root root 3923364 Dec  6 19:22 start_x.elf

The kernel is kernel7.img (older pis may expect kernel.img instead). 
The rest of the files are the pi's firmware packet, from github.

E. Liddell