From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 01/10] dt/bindings: Add binding for BCM2835 mailbox driver Date: Tue, 17 Mar 2015 19:52:12 -0600 Message-ID: <5508DA4C.6050800@wwwdotorg.org> References: <1425329684-23968-1-git-send-email-eric@anholt.net> <1425329684-23968-2-git-send-email-eric@anholt.net> <20150303080550.GF6976@x1> <87vbih98za.fsf@eliezer.anholt.net> <54F66FDD.2040409@wwwdotorg.org> <87egothkaf.fsf@eliezer.anholt.net> <55079AA0.5090904@wwwdotorg.org> <87vbhzl9t1.fsf@eliezer.anholt.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87vbhzl9t1.fsf-omZaPlIz5HhaEpDpdNBo/KxOck334EZe@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Eric Anholt Cc: Lee Jones , linux-arm-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jassi Brar , Craig McGeachie , Lubomir Rintel List-Id: devicetree@vger.kernel.org On 03/17/2015 01:10 PM, Eric Anholt wrote: > Stephen Warren 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html