On 03/17/2015 01:10 PM, Eric Anholt wrote: > Stephen Warren <swarren@xxxxxxxxxxxxx> writes: > >> On 03/12/2015 05:23 PM, Eric Anholt wrote: >>> Device base maintainers weren't excited about my patch for >>> -EPROBE_DEFER, because then a new DT would mean we start >>> failing to probe the USB driver in an older kernel, which >>> whould be a regression in the case that the user had U-Boot >>> setting up USB for them. >> >> The main ABI issue is that old DTs should work with new kernels. >> The other way around is nice, but certainly not as strict a >> requirement. I don't think that should block a change. Do you >> have a link to the thread; I don't think I noticed it. > > http://comments.gmane.org/gmane.linux.kernel/1906119 Hmm. I think that in general, the Linux kernel has already chosen deferred probe as the ordering mechanism over fixed init levels, which have demonstrably been unable to solve all ordering problems in the past. As Kevin pointed out, new DT with old kernel isn't the most important use-case. The only other objection I saw was Ulf not wanting to introduce another "probe scenario", but I guess he changed his mind since he outlines the steps to make deferred probe work in a later email. I guess/hope the way forward is to either wait for PM domains to work with deferred probe, or push that work forward (i.e. implement part (1) mentioned in Ulf's Mar 16 email). -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
