Hi Simon, On Fri, Jul 14, 2017 at 07:47:45AM -0600, Simon Glass wrote: > On 5 July 2017 at 14:14, Maxime Ripard <maxime.rip...@free-electrons.com> > wrote: > > On Wed, Jul 05, 2017 at 04:57:40PM +0200, Maxime Ripard wrote: > >> On Tue, Jul 04, 2017 at 01:33:25PM -0600, Simon Glass wrote: > >> > Hi Maxime, > >> > > >> > On 21 June 2017 at 01:31, Maxime Ripard > >> > <maxime.rip...@free-electrons.com> wrote: > >> > > Hi Simon, > >> > > > >> > > On Mon, Jun 19, 2017 at 11:11:27AM -0600, Simon Glass wrote: > >> > >> Add a driver-model version of this driver which mostly uses the > >> > >> existing > >> > >> code. The old code can be removed once all boards are switched over. > >> > >> > >> > >> Signed-off-by: Simon Glass <s...@chromium.org> > >> > > > >> > > I'm not sure if you tested that, but we have some code that switches > >> > > the MMC indices when using both an eMMC and an external MMC. > >> > > > >> > > http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/board.c#l494 > >> > > > >> > > This predates my time, but it seems that it was done to have a > >> > > consistent boot MMC device ID. > >> > > > >> > > I'm not really sure we can get rid of it (even if it creates some > >> > > issues of it's own), but what would be the impact of a switch to the > >> > > device model on that logic? > >> > > >> > That is a pretty terrible hack. > >> > >> Yes, I know. This is especially bad when used together with other > >> tools that rely on one MMC index for example (such as fastboot). > >> > >> I wanted to kill it for quite some time, but I'm a bit reluctant due > >> to the possible side effects. > >> > >> > I'm not sure whether it will continue to work with DM. It does still > >> > use the device number in the block device, so maybe... Do you have > >> > a board would use this? > >> > >> I guess I do. I'll give it a try or tonight and let you know. > > > > I just tested. Even with an eMMC (which was the first use case for > > that hack), it works, even things that are not mainline yet (fastboot, > > etc). > > > > It obviously break the old scripts relying on the mmc index, but I > > guess that's ok. > > > > There's one regression though. Our eMMC will always be the second one, > > which means that the distro bootargs will always boot on the external > > SD first (which is always going to be mmc0). > > > > That's due to the fact that the eMMC controller is the third one, and > > is thus probed last. We obviously want something deterministic for > > fastboot for example, but booting partitions of the media you started > > from make sense I guess. And this is what this hack was trying to > > address. > > OK...so what should we do here?
I guess we should just drop the hack. We'll have to at some point anyway. But I guess we should also find a way to tweak the distro bootcmd at boot time to search for the medium that we booted on first. I'm not really sure how to do this though. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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