RE: [PATCH v6 01/11] mtd: core: always create master device

Usyskin, Alexander
2025-06-09T12:23:55Z

> Subject: Re: [PATCH v6 01/11] mtd: core: always create master device
>
>
> >>>> Several of my qemu boot tests fail to boot from mtd devices with this
> patch
> >>>> in the mainline kernel. Reverting it fixes the problem. As far as I can
> >>>> see this affects configurations with
> CONFIG_MTD_PARTITIONED_MASTER=y
> >>>> when
> >>>> trying to boot from an mtd partition other than mtdblock0, with the
> >>>> mtd partition data in devicetree (.../aspeed/openbmc-flash-layout.dtsi).
> >>>> Is there a guidance describing the changed behavior, by any chance,
> >>>> and how the boot command line now needs to look like when using one
> of
> >>>> the flash partitions as root file system ?
> >>>>
> >>>> Thanks,
> >>>> Guenter
> >>>
> >>> I've tried to make is as transparent as possible for the existing users.
> >>> Only change is that now every partition has master that is not partitioned.
> >>> Is the CONFIG_MTD_PARTITIONED_MASTER=n fixed the problem for you?
> >> No change is expected, can you please describe the devices that you
> >> observe with and without the patch? Maybe there is something wrong in
> >> the core logic.
> >>
> >
> > I am trying to boot supermicro-x11spi-bmc in qemu from flash partition 6.
> > The qemu command line is something like
> >
> > qemu-system-arm -M supermicro-x11spi-bmc,fmc-
> model=n25q256a13,spi-model=n25q256a13 \
> > -kernel arch/arm/boot/zImage -no-reboot -snapshot \
> > -audio none \
> > -drive file=/tmp/flash,format=raw,if=mtd,index=1 \
> > -nic user \
> > --append "root=/dev/mtdblock6 rootwait console=ttyS4,115200
> earlycon=uart8250,mmio32,0x1e784000,115200n8" \
> > -dtb arch/arm/boot/dts/aspeed/aspeed-bmc-supermicro-x11spi.dtb
> \
> > -nographic -monitor null -serial stdio
> >
> > This is with aspeed_g5_defconfig. Note that the flash models need to be
> specified.
> > The default flashes are no longer recognized when booting from qemu since
> commit
> > 947c86e481a0 ("mtd: spi-nor: macronix: Drop the redundant flash info
> fields").
> >
> > The above only works with this patch reverted (or with v6.15 and older, of
> course).
> >
> > Guenter
>
> Alexander, can you please investigate? We need a fix because Guenter
> might not be the only affecter user. Otherwise this patch can't stand,
> unfortunately.
>
> Thanks,
> Miquèl

Maybe something is moved, and it is not /dev/mtdblock6 now.

Guenter, if it works with CONFIG_MTD_PARTITIONED_MASTER=n, can
you dump the list of devices that you can see?

- -
Thanks,
Sasha