On 06/04/2023 19:32, Marek Vasut wrote: > On 4/6/23 18:36, Krzysztof Kozlowski wrote: >> On 05/04/2023 20:24, Christoph Niedermaier wrote: >>> From: Marek Vasut [mailto:marex@xxxxxxx] >>> Sent: Wednesday, April 5, 2023 6:25 PM >>>> On 4/5/23 18:02, Christoph Niedermaier wrote: >>>> >>>> [...] >>>> >>>>> +/ { >>>>> + model = "DH electronics i.MX6ULL DHCOR on maveo box"; >>>>> + compatible = "dh,imx6ull-dhcor-maveo-box", "dh,imx6ull-dhcor-som", >>>>> + "fsl,imx6ull"; >>>>> + >>>>> + aliases { >>>>> + /delete-property/ mmc0; /* Avoid double definitions */ >>>>> + /delete-property/ mmc1; >>>>> + mmc2 = &usdhc2; /* eMMC should be mmc2 */ >>>> >>>> Why not mmc0 ? >>>> >>>> Use root=PARTUUID= when booting to avoid any dependency on >>>> root=/dev/mmcblk2pN enumeration. >>> >>> This is due to software interchangeability with the DHCOM >>> i.MX6ULL, where the eMMC is always mmc2. >> >> That's not the reason to have aliases. The number should match numbering >> in your datasheet/schematics/user-guide, not what your software wants. >> >> Use PARTUUID for SW dependencies. > > Regarding the PARTUUID, Christoph raised a valid concern I think. These > machines can come with A/B update scheme, where the PARTUUID could > become identical between two partitions. Or, you can write the same > image to both eMMC and SD card. I don't think PARTUUID is the silver > bullet solution, but I agree the enumeration is a great solution either. If you remove other aliases it means it comes only with emmc, right? One storage. Then any A/B means you have two partitions. Two partitions will have different PARTUUID as partition number is there. You can also use PARTLABEL=root_a (root_b). That's BTW easy way to switch between A/B partitions. Best regards, Krzysztof
