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

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: "Usyskin, Alexander" <alexander.usyskin@intel.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Vignesh Raghavendra" <vigneshr@ti.com>,
	"De Marchi, Lucas" <lucas.demarchi@intel.com>,
	"Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
	"Vivi, Rodrigo" <rodrigo.vivi@intel.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Tvrtko Ursulin" <tursulin@ursulin.net>,
	"Poosa, Karthik" <karthik.poosa@intel.com>,
	"Abliyev, Reuven" <reuven.abliyev@intel.com>,
	"Weil, Oren jer" <oren.jer.weil@intel.com>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 01/11] mtd: core: always create master device
Date: Mon, 09 Jun 2025 11:43:19 +0200	[thread overview]
Message-ID: <87ikl5xnbc.fsf@bootlin.com> (raw)
In-Reply-To: <2f3d3ff9-e483-42cc-aaed-f376d46a6701@roeck-us.net> (Guenter Roeck's message of "Sun, 8 Jun 2025 17:59:37 -0700")

>>>> 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