From: Christian Zigotzky <hidden> Date: 2026-07-01 13:03:33
Hello,
Here is the email without HTML (Sorry):
The Nemo board [1] doesn’t boot without this patch. Darren explained it really well:
Originally we initialised the PCI-e ports in setup arch, this is quite early, and it seems uses some kernel functions that were not recommended (They changed a whole lot of different platforms at the same time for the same reason)
After this we added the ISA bridge, then the kernel would init the IRQ contollers.
The patch that broke booting on the X1000 moved the pas_pci_init to a node in the machine description, where it called later in the boot sequence. Unfortunately this is after we've tried to add the i8259 contoller from the pas_init_IRQ. Since our ISA bridge can't be found until we've connected the PCI-e ports the system tries to write to registers that aren't yet mapped - result a kernel panic, but before console I/O has been initialised so it appears to be a hang. We had a similar problem when they were introducing Radix support.
My patch changes our code so that it works with the new kernel code in place. Basically I moved the code that adds the i8259 cascade to after we've scanned for the ISA bridge where I know it will work.
Hopefully this makes sense, shout out if it doesn't.
Regards
Darren
[1] https://en.wikipedia.org/wiki/AmigaOne_X1000
Signed-off-by: Christian Zigotzky <redacted>
---
arch/powerpc/platforms/pasemi/pci.c | 7 +++++++
arch/powerpc/platforms/pasemi/setup.c | 7 ++++---
2 files changed, 11 insertions(+), 3 deletions(-)
From: Christian Zigotzky <hidden> Date: 2026-07-28 12:50:59
On 27/07/26 15:43, Christophe Leroy (CS GROUP) wrote:
>
> Should be better in arch/powerpc/platforms/pasemi/pasemi.h
>
Hello Christophe,
Thank you for your answer. I modified the patch today. The Nemo board
boots without any problems if I compile the RC5 of kernel 7.2 with this
patch.
Could you please check the following modified patch?
Thanks,
Christian
---
powerpc/pasemi: Move Nemo i8259 initialization to pci.c
The Nemo board requires the PCIe ports to be initialized before the
SB600 ISA bridge can be accessed.
Since pas_pci_init() is now called later during boot, the i8259
initialization in pas_init_IRQ() happens too early and accesses
registers that are not yet mapped, preventing the board from booting.
Move the Nemo-specific i8259 initialization to pas_add_bridge(),
after the ISA bridge has been discovered.
Suggested-by: Darren Stevens <redacted>
Tested-by: Christian Zigotzky <redacted>
Signed-off-by: Christian Zigotzky <redacted>
---
v2:
- Move Nemo i8259 initialization out of pas_init_IRQ() and into
pas_add_bridge() after the ISA bridge has been discovered.
- Change nemo_init_IRQ() to no longer depend on the MPIC instance passed
from the IRQ setup path.
- Move the nemo_init_IRQ() declaration to pasemi.h and add a no-op stub
for non-Nemo builds.
- Fix missing prototype warning reported by Christophe Leroy.
- Fix indentation and clean up the commit message.
diff -rupN a/arch/powerpc/platforms/pasemi/pasemi.h
b/arch/powerpc/platforms/pasemi/pasemi.h
Le 28/07/2026 à 14:50, Christian Zigotzky a écrit :
On 27/07/26 15:43, Christophe Leroy (CS GROUP) wrote:
>
> Should be better in arch/powerpc/platforms/pasemi/pasemi.h
>
Hello Christophe,
Thank you for your answer. I modified the patch today. The Nemo board
boots without any problems if I compile the RC5 of kernel 7.2 with this
patch.
Could you please check the following modified patch?
b4 doesn't see it as a patch. Can you resend as a regular patch ?
$ b4 shazam --single-message
f5ed5a79-4235-31b6-5bd9-c68d1a6b50cf@xenosoft.de
Single-message mode, ignoring any follow-ups
Grabbing thread from
lore.kernel.org/all/f5ed5a79-4235-31b6-5bd9-c68d1a6b50cf@xenosoft.de/t.mbox.gz
Analyzing 1 messages in the thread
No patches found.
Thanks
Christophe
quoted hunk
Thanks,
Christian
---
powerpc/pasemi: Move Nemo i8259 initialization to pci.c
The Nemo board requires the PCIe ports to be initialized before the
SB600 ISA bridge can be accessed.
Since pas_pci_init() is now called later during boot, the i8259
initialization in pas_init_IRQ() happens too early and accesses
registers that are not yet mapped, preventing the board from booting.
Move the Nemo-specific i8259 initialization to pas_add_bridge(),
after the ISA bridge has been discovered.
Suggested-by: Darren Stevens <redacted>
Tested-by: Christian Zigotzky <redacted>
Signed-off-by: Christian Zigotzky <redacted>
---
v2:
- Move Nemo i8259 initialization out of pas_init_IRQ() and into
pas_add_bridge() after the ISA bridge has been discovered.
- Change nemo_init_IRQ() to no longer depend on the MPIC instance passed
from the IRQ setup path.
- Move the nemo_init_IRQ() declaration to pasemi.h and add a no-op stub
for non-Nemo builds.
- Fix missing prototype warning reported by Christophe Leroy.
- Fix indentation and clean up the commit message.
diff -rupN a/arch/powerpc/platforms/pasemi/pasemi.h b/arch/powerpc/
platforms/pasemi/pasemi.h
From: Philip Li <hidden> Date: 2026-08-16 05:52:32
On Sat, Aug 15, 2026 at 11:56:56AM +0200, Christian Zigotzky wrote:
On 14/08/26 17:42, kernel test robot wrote:
quoted
Hi Christian,
kernel test robot noticed the following build warnings:
[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/fixes linus/master v7.2-rc7