On Thu, Jul 25, 2013 at 10:28:38AM -0700, Stephen Warren wrote: > On 07/24/2013 02:09 AM, Steffen Trumtrar wrote: > > Hi! > > > > Embedded devices often use multiple SD/MMC devices as boot/rootfs disks. > > Some of them are removable, some not. If the removable cards are not > > present, but are probed before the non-removable ones, the indexing > > scheme changes. This makes it harder to hard-code the rootfs in the > > cmdline. > > > > First solution I came up with was the alias-node in DT. > > I guess my implementation is pretty hacky and ugly, but you can get lost > > pretty fast in the whole mmc stack. > > For example, the second patch should use "card->host->index" instead of parsing > > the alias again, I guess. I'm not sure why it currently doesn't though. > > This has been discussed a few times before and rejected IIRC. One issue > is that block device ID is actually decoupled from host controller ID > anyway, e.g. if a removable device is mounted, removed, and then > re-plugged the new device can get a different ID, so this approach > doesn't really work in all cases anyway. > Hm, okay. I actually wasn't aware of the older discussions. > > So, if there is a better place or solution to specify a reliable ordering > > of mmc devices, please let me hear it. > > root=UUID=xxx or root=PARTUUID=xxx are the best solution. With recent > U-Boot, you can enable and use the "part" command to find the partition > UUID automatically, and hence not need to hard-code anything. Something > similar could presumably be implemented for other bootloaders. I am actually okay with that. I know barebox can do that, but didn't knew that U-Boot is also capabable of that. So, I'm okay with dropping the patch. Thanks, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
