Hi,

I have recently thought about replaying my aging Banana Pi machines
with recent Raspberry Pi 4 machines. I also have a limited number of
Raspberry Pi 3 that run Raspbian. Being a seasoned Debian guy, I'd
like to run plain Debian on those machines.

Thanks to the work of a few Debian Developers, there are ready-to-run
Debian images for the Raspberry Pi available, and the Debian Wiki has
some documentation:

https://wiki.debian.org/RaspberryPi4" rel="nofollow" target="_blank">https://wiki.debian.org/RaspberryPi4
https://wiki.debian.org/RaspberryPi

I have a few questions about this, and I do hope that I find
knowledgearble people on here.

Generally, I'd like to have a better understanding what "upstream
kernel" means in this context. Is this the kernel.org kernel or the
Raspberry OS kernel or some third project providing kernel sources for
the Raspi? Will a kernel.org kernel work? Will a Debian.org kernel
work?

What is the correct X server to use for a Raspberry Pi 4?

Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
kernel compiled from github.com/raspberrypi?

Does the Raspberry Pi 4 boot from the GPU as well as the older
devices?

Does "3d applications will require Pi specific builds" mean that for
example, the KDE compositor in Debian will not run at all, or will it
just run unaccelerated? How would a Pi specific build be done, would
that need code changes or just some special library compiled in?

Do the issues listed in
https://wiki.debian.org/RaspberryPi#Raspberry_Pi_issues still apply to
the current devices?

Does the "host Debian machine" mentioned in the QEMU User Emulation
chapter need to be ARM? Or can I do that on a fat AMD64 box? Can QEMU
User Emulation be used to compile and build packages destined to be
run on real hardware?

Greetings
Marc

--
-------------------------------------- !! No courtesy copies, please !! -----
Marc Haber | " Questions are the | Mailadresse im Header
Mannheim, Germany | Beginning of Wisdom " |
Nordisch by Nature | Lt. Worf, TNG "Rightful Heir" | Fon: *49 621 72739834

On Sat, 24 Apr 2021 13:06:06 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:

> Hi,
>
> I have recently thought about replaying my aging Banana Pi machines
> with recent Raspberry Pi 4 machines. I also have a limited number of
> Raspberry Pi 3 that run Raspbian. Being a seasoned Debian guy, I'd
> like to run plain Debian on those machines.

I'm running Mageia 8 on a rpi4, available on the various mirrors such as
http://mirror.math.princeton.edu/pub/mageia/distrib/8/aarch64/install/images/

> Thanks to the work of a few Debian Developers, there are ready-to-run
> Debian images for the Raspberry Pi available, and the Debian Wiki has
> some documentation:
>
> https://wiki.debian.org/RaspberryPi4" rel="nofollow" target="_blank">https://wiki.debian.org/RaspberryPi4
> https://wiki.debian.org/RaspberryPi
>
> I have a few questions about this, and I do hope that I find
> knowledgearble people on here.
>
> Generally, I'd like to have a better understanding what "upstream
> kernel" means in this context. Is this the kernel.org kernel or the
> Raspberry OS kernel or some third project providing kernel sources for
> the Raspi? Will a kernel.org kernel work? Will a Debian.org kernel
> work?

Mageia is using kernel.org's source with some custom patches.

> What is the correct X server to use for a Raspberry Pi 4?

Mageia is using x11/xorg version 1.20.11.

> Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
> kernel compiled from github.com/raspberrypi?

It's working for Mageia.

> Does the Raspberry Pi 4 boot from the GPU as well as the older
> devices?

No idea what you mean by booting from the gpu. I'm booting from an sd card,
though I understand an external ssd can be added. I have no experience with
that.

> Does "3d applications will require Pi specific builds" mean that for
> example, the KDE compositor in Debian will not run at all, or will it
> just run unaccelerated? How would a Pi specific build be done, would
> that need code changes or just some special library compiled in?
>
> Do the issues listed in
> https://wiki.debian.org/RaspberryPi#Raspberry_Pi_issues still apply to
> the current devices?
>
> Does the "host Debian machine" mentioned in the QEMU User Emulation
> chapter need to be ARM? Or can I do that on a fat AMD64 box? Can QEMU
> User Emulation be used to compile and build packages destined to be
> run on real hardware?

The rest I can't answer. Plasma and Gnome both work. The only problem I've
encountered with it, which is still being worked on, is that sound over hdmi
is not currently working with Mageia installations. It does work if I use
the raspberry os.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

"David W. Hodgins" <dwhodgins@nomail.afraid.org> wrote:
>On Sat, 24 Apr 2021 13:06:06 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
>> Generally, I'd like to have a better understanding what "upstream
>> kernel" means in this context. Is this the kernel.org kernel or the
>> Raspberry OS kernel or some third project providing kernel sources for
>> the Raspi? Will a kernel.org kernel work? Will a Debian.org kernel
>> work?
>
>Mageia is using kernel.org's source with some custom patches.

Do they publish those patches?

>> What is the correct X server to use for a Raspberry Pi 4?
>
>Mageia is using x11/xorg version 1.20.11.

Yes, but which flavor? For example, my Notebook uses
xserver-xorg-video-intel. On the Pi, I have xerver-xorg-video-fbdev
and xserver-xorg-video-vesa installed, glxgears seems to run fine, but
I doubt that the hardwar acceleration is properly working.
Responsiveness is unsatisfactory, youtube is jumpy nearly unuseable.

I guess that 2 GB is too little memory and/or the SD card is too slow.

>> Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
>> kernel compiled from github.com/raspberrypi?
>
>It's working for Mageia.

How do you check that?

>> Does the Raspberry Pi 4 boot from the GPU as well as the older
>> devices?
>
>No idea what you mean by booting from the gpu. I'm booting from an sd card,
>though I understand an external ssd can be added. I have no experience with
>that.

From what I understand, on at least the older Raspi the CPU doesnt
start by itself. It's the GPU that comes alive first and reads a
binary firmware blob from the SD card which is then in turn used to
initialize and boot the rest of the hardware including the CPU. What
you see from the boot process, and what Linuxsers consider the system
boot, happens after this. From what I understand, config.txt and
cmdline.txt are also read by the GPU before the CPU starts up.

As far as I see, it's the same for the Raspi 4.

>The rest I can't answer. Plasma and Gnome both work. The only problem I've
>encountered with it, which is still being worked on, is that sound over hdmi
>is not currently working with Mageia installations. It does work if I use
>the raspberry os.

Sound over HDMI works for me.

Greetings
Marc
--
-------------------------------------- !! No courtesy copies, please !! -----
Marc Haber | " Questions are the | Mailadresse im Header
Mannheim, Germany | Beginning of Wisdom " |
Nordisch by Nature | Lt. Worf, TNG "Rightful Heir" | Fon: *49 621 72739834

On Sun, 25 Apr 2021 06:12:29 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:

> "David W. Hodgins" <dwhodgins@nomail.afraid.org> wrote:
>> On Sat, 24 Apr 2021 13:06:06 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
>>> Generally, I'd like to have a better understanding what "upstream
>>> kernel" means in this context. Is this the kernel.org kernel or the
>>> Raspberry OS kernel or some third project providing kernel sources for
>>> the Raspi? Will a kernel.org kernel work? Will a Debian.org kernel
>>> work?
>>
>> Mageia is using kernel.org's source with some custom patches.
>
> Do they publish those patches?

Of course. They are included in the srpm, The build system creates the i586,
x86-64, and aarch64 (rpi4) packages from the same srpm, and the patches are
included. The srpm packages are on the mirrors along with the regular packages.

>>> What is the correct X server to use for a Raspberry Pi 4?
>>
>> Mageia is using x11/xorg version 1.20.11.

> Yes, but which flavor? For example, my Notebook uses
> xserver-xorg-video-intel. On the Pi, I have xerver-xorg-video-fbdev
> and xserver-xorg-video-vesa installed, glxgears seems to run fine, but
> I doubt that the hardwar acceleration is properly working.
> Responsiveness is unsatisfactory, youtube is jumpy nearly unuseable.

Ah. Which video module. I hadn't previously checked that as it's working ok.
There is no /etc/X11/xorg.conf, so it' letting xorg select the video modules.

Checking /var/log/Xorg.0.log ...
# grep modules /var/log/Xorg.0.log
[ 23.349] (**) ModulePath set to "/usr/lib64/xorg/extra-modules,/usr/lib64/xorg/modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules"
[ 23.356] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so
[ 23.362] (II) Loading /usr/lib64/xorg/modules/drivers/modesetting_drv.so
[ 23.371] (II) Loading /usr/lib64/xorg/modules/drivers/fbdev_drv.so
[ 23.373] (II) Loading /usr/lib64/xorg/modules/libfbdevhw.so
[ 23.377] (II) Loading /usr/lib64/xorg/modules/libfb.so
[ 23.378] (II) Loading /usr/lib64/xorg/modules/libshadow.so

So it's using the x11-driver-video-fbdev driver.

> I guess that 2 GB is too little memory and/or the SD card is too slow.

The rpi4 4 Model B I have has 4G ram. With firefox playing a youtube video ...
# free -m
total used free shared buff/cache available
Mem: 3831 1577 1093 108 1160 1975
Swap: 6696 0 6696

The video plays fine, but as before the Mageia kernel has a problem detecting
the sound device(s).

>>> Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
>>> kernel compiled from github.com/raspberrypi?
>>
>> It's working for Mageia.

> How do you check that?

glxspheres runs. It's slow but it works.

>>> Does the Raspberry Pi 4 boot from the GPU as well as the older
>>> devices?
>>
>> No idea what you mean by booting from the gpu. I'm booting from an sd card,
>> though I understand an external ssd can be added. I have no experience with
>> that.
>
> From what I understand, on at least the older Raspi the CPU doesnt
> start by itself. It's the GPU that comes alive first and reads a
> binary firmware blob from the SD card which is then in turn used to
> initialize and boot the rest of the hardware including the CPU. What
> you see from the boot process, and what Linuxsers consider the system
> boot, happens after this. From what I understand, config.txt and
> cmdline.txt are also read by the GPU before the CPU starts up.
>
> As far as I see, it's the same for the Raspi 4.

I believe so. I haven't read the Raspberry os manual, and only used it long
enough to ensure the hardware works before switching to the Mageia install.
I've been involved with Mageia since it started, so am familiar with how it
does things. You're explanation explains the messages that show on the screen
prior to what's available in the journal or dmesg. I hadn't paid much attention
to them.

>> The rest I can't answer. Plasma and Gnome both work. The only problem I've
>> encountered with it, which is still being worked on, is that sound over hdmi
>> is not currently working with Mageia installations. It does work if I use
>> the raspberry os.
>
> Sound over HDMI works for me.

Thanks for the pointer to config.txt (found it in /boot/EFI/). I'll compare
that to what raspberry os uses to see if that's the cause of the sound problems.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

"David W. Hodgins" <dwhodgins@nomail.afraid.org> wrote:
>On Sun, 25 Apr 2021 06:12:29 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
>> "David W. Hodgins" <dwhodgins@nomail.afraid.org> wrote:
>>> On Sat, 24 Apr 2021 13:06:06 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
>>>> Generally, I'd like to have a better understanding what "upstream
>>>> kernel" means in this context. Is this the kernel.org kernel or the
>>>> Raspberry OS kernel or some third project providing kernel sources for
>>>> the Raspi? Will a kernel.org kernel work? Will a Debian.org kernel
>>>> work?
>>>
>>> Mageia is using kernel.org's source with some custom patches.
>>
>> Do they publish those patches?
>
>Of course. They are included in the srpm, The build system creates the i586,
>x86-64, and aarch64 (rpi4) packages from the same srpm, and the patches are
>included. The srpm packages are on the mirrors along with the regular packages.

I have in the mean time found out that a vanilla kernel will actually
run AND deliver accelerated graphics. I can even cross-compile the
kernel on my Ryzen desktop which is an order of magnitude faster. The
vc4 module needs to be manually loaded.

glxgears runs with > 100 fps, and I have a /dev/dri/card0. Is that
enough evidence for accelerated graphics, or should I do more checks?

>>>> What is the correct X server to use for a Raspberry Pi 4?
>>>
>>> Mageia is using x11/xorg version 1.20.11.
>
>> Yes, but which flavor? For example, my Notebook uses
>> xserver-xorg-video-intel. On the Pi, I have xerver-xorg-video-fbdev
>> and xserver-xorg-video-vesa installed, glxgears seems to run fine, but
>> I doubt that the hardwar acceleration is properly working.
>> Responsiveness is unsatisfactory, youtube is jumpy nearly unuseable.
>
>Ah. Which video module.

Sorry for the wrong terminology. In debian, the packages are called
xserver-xorg-video-foo and that misled me into thinking that the
module is the actual server.

># grep modules /var/log/Xorg.0.log
>[ 23.349] (**) ModulePath set to "/usr/lib64/xorg/extra-modules,/usr/lib64/xorg/modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules"
>[ 23.356] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so
>[ 23.362] (II) Loading /usr/lib64/xorg/modules/drivers/modesetting_drv.so
>[ 23.371] (II) Loading /usr/lib64/xorg/modules/drivers/fbdev_drv.so
>[ 23.373] (II) Loading /usr/lib64/xorg/modules/libfbdevhw.so
>[ 23.377] (II) Loading /usr/lib64/xorg/modules/libfb.so
>[ 23.378] (II) Loading /usr/lib64/xorg/modules/libshadow.so
>
>So it's using the x11-driver-video-fbdev driver.

Confirmed. Some resources on the web refer to an "fbturbo" module, but
that seems to be historic information.

>> I guess that 2 GB is too little memory and/or the SD card is too slow.
>
>The rpi4 4 Model B I have has 4G ram. With firefox playing a youtube video ...
># free -m
> total used free shared buff/cache available
>Mem: 3831 1577 1093 108 1160 1975
>Swap: 6696 0 6696
>
>The video plays fine, but as before the Mageia kernel has a problem detecting
>the sound device(s).

Sound over HDMI seems to work reasonably well on my machine. Didn't
test any other sound interface yet, I don't need that for the intended
use case.

>>>> Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
>>>> kernel compiled from github.com/raspberrypi?
>>>
>>> It's working for Mageia.
>
>> How do you check that?
>
>glxspheres runs. It's slow but it works.

glxpheres doesn't seem to be packaged in Debian.

>> From what I understand, on at least the older Raspi the CPU doesnt
>> start by itself. It's the GPU that comes alive first and reads a
>> binary firmware blob from the SD card which is then in turn used to
>> initialize and boot the rest of the hardware including the CPU. What
>> you see from the boot process, and what Linuxsers consider the system
>> boot, happens after this. From what I understand, config.txt and
>> cmdline.txt are also read by the GPU before the CPU starts up.
>>
>> As far as I see, it's the same for the Raspi 4.
>
>I believe so. I haven't read the Raspberry os manual, and only used it long
>enough to ensure the hardware works before switching to the Mageia install.
>I've been involved with Mageia since it started, so am familiar with how it
>does things. You're explanation explains the messages that show on the screen
>prior to what's available in the journal or dmesg. I hadn't paid much attention
>to them.

Anyway, the Debian images available to start do seem to do things
right. There are many different methods to actually boot Linux on the
Raspi 4. Debian just puts the kernel command line into config.txt,
which is then read during system boot. That's the most simple version
of doing things, making it hard to go back to a known-good kernel in
the failure case (one needs to pull the memory card from the raspi and
fix it on a different system).

There are also methods to use grub or even an EFI firmware to boot the
Raspi, but I haven't gone that way yet. Having grub sounds really
nice.

>>> The rest I can't answer. Plasma and Gnome both work. The only problem I've
>>> encountered with it, which is still being worked on, is that sound over hdmi
>>> is not currently working with Mageia installations. It does work if I use
>>> the raspberry os.
>>
>> Sound over HDMI works for me.
>
>Thanks for the pointer to config.txt (found it in /boot/EFI/). I'll compare
>that to what raspberry os uses to see if that's the cause of the sound problems.

So Mageia is actually using EFI. That is neat.

Greetings
Marc
--
-------------------------------------- !! No courtesy copies, please !! -----
Marc Haber | " Questions are the | Mailadresse im Header
Mannheim, Germany | Beginning of Wisdom " |
Nordisch by Nature | Lt. Worf, TNG "Rightful Heir" | Fon: *49 621 72739834

On Thu, 13 May 2021 03:53:33 -0400, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
> glxgears runs with > 100 fps, and I have a /dev/dri/card0. Is that
> enough evidence for accelerated graphics, or should I do more checks?

Like with the Mageia kernel, it's using framebuffer mode (fb) with vesa video
driver, so not accelerated, but fast enough for most purposes such as videos.
Just wouldn't work well for some games that require much higher fps.

>>>>> What is the correct X server to use for a Raspberry Pi 4?
>> # grep modules /var/log/Xorg.0.log
>> [ 23.349] (**) ModulePath set to "/usr/lib64/xorg/extra-modules,/usr/lib64/xorg/modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules"
>> [ 23.356] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so
>> [ 23.362] (II) Loading /usr/lib64/xorg/modules/drivers/modesetting_drv.so
>> [ 23.371] (II) Loading /usr/lib64/xorg/modules/drivers/fbdev_drv.so
>> [ 23.373] (II) Loading /usr/lib64/xorg/modules/libfbdevhw.so
>> [ 23.377] (II) Loading /usr/lib64/xorg/modules/libfb.so
>> [ 23.378] (II) Loading /usr/lib64/xorg/modules/libshadow.so
>>
>> So it's using the x11-driver-video-fbdev driver.

>>>>> Will accelerated 3d graphics on the Raspberry Pi 4 only run with a
>>>>> kernel compiled from github.com/raspberrypi?
>>>>
>>>> It's working for Mageia.
>>
>>> How do you check that?

I should have clarified. Playing youtube is working ok on an hdmi monitor.
It is not using accelerated 3d graphics. The video controller on the pi isn't
capable of it.

I guess it also depends on what video is chosen as they can have different frame
rates, bits/pixel, etc.

> There are also methods to use grub or even an EFI firmware to boot the
> Raspi, but I haven't gone that way yet. Having grub sounds really
> nice.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.