Re: [ANNOUNCE] v5.4.10-rt5

From: Gene Heskett <gheskett@shentel.net>
To: "linux-rt-users" <linux-rt-users@vger.kernel.org>
Subject: Re: [ANNOUNCE] v5.4.10-rt5
Date: Tue, 14 Jan 2020 11:23:29 -0500	[thread overview]
Message-ID: <202001141123.29884.gheskett@shentel.net> (raw)
In-Reply-To: <CAD56B7cgPfbcx8MNtYosOwhPi6fy+fqdauLsayR65dAg1yaYSg@mail.gmail.com>

On Tuesday 14 January 2020 08:54:30 Paul Thomas wrote:

> On Sun, Jan 12, 2020 at 9:44 PM Gene Heskett <gheskett@shentel.net> 
wrote:
> > On Friday 10 January 2020 15:14:30 Sebastian Andrzej Siewior wrote:
> > > Dear RT folks!
> > >
> > > I'm pleased to announce the v5.4.10-rt5 patch set.
> > >
> > > Changes since v5.4.10-rt4:
> > >
> > >   - Dick Hollenbeck reported that the printk rework had a negative
> > >     impact on the 8250 driver if not used as a console. Patch by
> > > John Ogness.
> > >
> > > Known issues
> > >      - None
> > >
> > > The delta patch against v5.4.10-rt4 is appended below and can be
> > > found here:
> > >
> > >
> > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.4/incr/patch
> > >-5.4 .10-rt4-rt5.patch.xz
> > >
> > > You can get this release via the git tree at:
> > >
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.gi
> > >t v5.4.10-rt5
> >
> > I grabbed a copy of this, then turned off anything not needed to run
> > LinuxCNC on an rpi4 in armhf config.  Then I noted its make had a
> > make deb-pkg option.  But it isn't making what I told it to make as
> > I'm sitting here watching it ALL go by. Did I miss something in  a
> > make menuconfig that triggered a make all? It was supposedly set for
> > armhf. But I'm even seeing x86 stuff go by. Obviously I know just
> > enough to screw it up. Point me at the right docs for arm builds
> > please.
> >
> > Hi Gene,
>
> I recently stumbled into deb-pkg, and it's awesome building up the
> source and standard debian packages all in one command, but it takes
> the same arguments as a standard make. For rpi4 this is arm64 not
> armhf so you probably want something like below to configure for
> arm64

armhf (32 bit) runs fine in on an RPI4, been doing it for a couple months 
now. With a 32 bit stack frame, context switch latencies are several 
microseconds better which linuxcnc loves. However with mesa interface 
cards handling all the sub-millisecond stuffs and using preempt-rt 
running in userspace, it all works quite well as the  max latency stays 
below 200 microseconds 99.99% of the time. Thats well within the 
servo-thread time of 1 millisecond the mesa cards need. 

> If you are doing this on the rpi4 you don't need the 
> CROSS_COMPILE= option.[1][2] make -j4 ARCH=arm64
> CROSS_COMPILE=aarch64-elf- defconfig
> Or if the kernel you're already running has a /proc/config.gz you can
> use that directly (zcat /proc/config.gz > .config).
> Then you can use the main make.

The kernel I an running was built, by me (queue the raspberry noises), 
with only the ondemand governer so while its working, its stuck in low 
gear. And the pi has plenty of cooling.

that kernel running now is a 4.19.71-rt24-v7l+ #1 SMP PREEMPT RT, but 
there has since been added another video speedup option, so ATM I am 
trying to build a 4.19.94-rt38 announced last week. But the git clone I 
pulled doesn't have the rt patch. And pulling that patch with curl today 
fails:

pi@rpi4:/media/pi/workspace $ curl  
http://www.kernel.org/pub/linux/kernel/projects/rt/4.19/patch-4.19.94-rt38.patch.xz
<html>
<head><title>301 Moved Permanently</title></head>
<body>
<center><h1>301 Moved Permanently</h1></center>
<hr><center>nginx</center>
</body>
</html>

But firefox pulled it, I've unpacked it, but the usual patch -p1 
<../patches/* syntax fails, ambiguous redirect 

Obviously a greenhorn at work, been running a linux only house since '98. 
And the wet ram is 85 yo.

Next? & thank you a bunch

> make -j4 ARCH=arm64 CROSS_COMPILE=aarch64-elf- deb-pkg
> Keep in mind that even with the debian package this may not be enough
> to install the kernel for u-boot correctly, You'll have to see if all
> the scripts in /etc/kernel/postinst.d/ are doing everything that is
> needed, but it should give you at least a /boot/vmlinuz... When I use
> this I have to extract the compressed Image to where u-boot grabs the
> kernel.
>
> Hope this helps.
>
> thanks,
> Paul
>
I have a recipe that installs to a u-boot already.

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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>