Re: [yocto] [meta-rockchip][PATCH] use uuid instead of hard-coding root device

From: "Trevor Woerner" <twoerner@gmail.com>
To: yocto@lists.yoctoproject.org
Subject: Re: [yocto] [meta-rockchip][PATCH] use uuid instead of hard-coding root device
Date: Mon, 20 Sep 2021 12:54:13 -0400	[thread overview]
Message-ID: <20210920165413.GA12087@localhost> (raw)
In-Reply-To: <16A5BB09DD6D5F75.29722@lists.yoctoproject.org>

On Fri 2021-09-17 @ 06:01:21 PM, Trevor Woerner via lists.yoctoproject.org wrote:
> Recent upstream kernel changes have made the mmc probing order unpredictable.
> Therefore, boards with both an emmc and sdmmc interface aren't guaranteed to
> boot with a hard-coded root device selected.
> 
> For example, on the rock64, with linux-yocto 5.10.y, using the uSD card (i.e.
> the sdmmc interface) about 50% of the time the boot would succeed, and roughly
> 50% of the time it wouldn't:
> 
> 	...
> 	[    0.612233] Waiting for root device /dev/mmcblk1p7...
> 	[    0.634551] mmc_host mmc1: Bus speed (slot 0) = 300000Hz (slot req 300000Hz, actual 300000HZ div = 0)
> 	[    0.639064] mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 50000000Hz, actual 50000000HZ di)
> 	[    0.640007] mmc0: new high speed SDXC card at address 5048
> 	[    0.641176] mmcblk0: mmc0:5048 SD64G 58.0 GiB
> 	[    0.647610] random: fast init done
> 	[    0.648279] GPT:Primary header thinks Alt. header is not at the end of the disk.
> 	[    0.648941] GPT:376479 != 121634815
> 	[    0.649252] GPT:Alternate GPT header not at the end of the disk.
> 	[    0.649796] GPT:376479 != 121634815
> 	[    0.650106] GPT: Use GNU Parted to correct GPT errors.
> 	[    0.650598]  mmcblk0: p1 p2 p3 p4 p5 p6 p7
> 
> NOTE the discrepancy between the kernel waiting for device /dev/mmcblk1p7,
> which comes from the hard-coded kernel cmdline, and the kernel probing putting
> the sdmmc on mmcblk0.
> 
> With linux-yocto 5.13.y on the rock64 using the uSD card the board would never
> boot, the sdmmc always appears on mmcblk0.
> 
> Instead of simply changing the hard-coded root device (i.e. from mmcblk0 to
> mmcblk1) switch to using partition UUIDs instead. Hard-coding the boot device
> would work with 5.13.y but would fail 50% of the time with 5.10.y; who knows
> what other kernels will do?
> 
> In any case, switching to UUIDs works regardless of board, kernel, or
> available mmc interfaces.
> 
> Boot tested on:
> - rock64
> - nanopi-m4-2gb
> - tinker-board
> - rock-pi-e
> - rock-pi-4b
> 
> Signed-off-by: Trevor Woerner <twoerner@gmail.com>
> ---
>  conf/machine/include/nanopi-m4.inc    |  2 --
>  conf/machine/include/rock-pi-4.inc    |  2 --
>  conf/machine/include/rockchip-wic.inc |  4 ----
>  conf/machine/rock64.conf              |  3 ---
>  conf/machine/tinker-board-s.conf      |  2 --
>  conf/machine/vyasa-rk3288.conf        |  2 --
>  wic/rockchip.wks                      | 16 ++++++++--------
>  7 files changed, 8 insertions(+), 23 deletions(-)

Applied to meta-rockchip master.