From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755765AbaENQXc (ORCPT ); Wed, 14 May 2014 12:23:32 -0400 Received: from h1446028.stratoserver.net ([85.214.92.142]:60429 "EHLO mail.ahsoftware.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752424AbaENQXb (ORCPT ); Wed, 14 May 2014 12:23:31 -0400 Message-ID: <53739871.9070407@ahsoftware.de> Date: Wed, 14 May 2014 18:23:13 +0200 From: Alexander Holler User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Grant Likely CC: Linux Kernel Mailing List , "devicetree@vger.kernel.org" , Jon Loeliger , Russell King , Greg Kroah-Hartman , Rob Herring , "linux-arm-kernel@lists.infradead.org" Subject: Re: [RFC PATCH 0/9] dt: dependencies (for deterministic driver initialization order based on the DT) References: <1399913280-6915-1-git-send-email-holler@ahsoftware.de> <20140514141914.446F7C4153D@trevor.secretlab.ca> <53738580.7000902@ahsoftware.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 14.05.2014 18:05, schrieb Grant Likely: > On Wed, May 14, 2014 at 4:02 PM, Alexander Holler wrote: >> Am 14.05.2014 16:19, schrieb Grant Likely: >> >> >>> Rather than a dtb schema change, for the most common properties (irqs, >>> clocks, gpios), we could extract dependencies at boot time. I don't like >>> the idea of adding a separate depends-on property because it is very >>> easy to get it out of sync with the actual binding data (dtc is not the >>> only tool that manipulates .dtbs. Firmware will fiddle with it too). >> >> >> Then that stuff has to fiddle correct. Sorry, but trying to solve all >> problems right from the beginning just leads to endless talks with no end >> and nothing will happen at all because nobody aggrees how to start. > > I appreciate the problem that you're trying to solve and why you're > using the dtc approach. My job is to poke at the solution and make > sure it is going to be reliable. Making sure all users know how to > fiddle with the new property correctly is not a trivial problem, > especially when it is firmware that will not necessarily be updated. The answer is just that they don't have to use this feature. It is more meant as a long-term solution to fix for the problem of increasing hard-coded workarounds which all are trying to fix the initialization order of drivers. Hardware has become a lot more complicated than it was in the good old days, and I think the time is right trying to adopt the init-system to this new century instead of still adding workarounds here and there. > I'm not saying flat out 'no' here, but before I merge anything, I have > to be reasonably certain that the feature is not going to represent a > maintenance nightmare over the long term. The maintenance nightmare is already present in form of all the workarounds which are trying to fix the initialzation order necessary for modern hardware. Regards, Alexander From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Holler Subject: Re: [RFC PATCH 0/9] dt: dependencies (for deterministic driver initialization order based on the DT) Date: Wed, 14 May 2014 18:23:13 +0200 Message-ID: <53739871.9070407@ahsoftware.de> References: <1399913280-6915-1-git-send-email-holler@ahsoftware.de> <20140514141914.446F7C4153D@trevor.secretlab.ca> <53738580.7000902@ahsoftware.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: Linux Kernel Mailing List , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jon Loeliger , Russell King , Greg Kroah-Hartman , Rob Herring , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org Am 14.05.2014 18:05, schrieb Grant Likely: > On Wed, May 14, 2014 at 4:02 PM, Alexander Holler wrote: >> Am 14.05.2014 16:19, schrieb Grant Likely: >> >> >>> Rather than a dtb schema change, for the most common properties (irqs, >>> clocks, gpios), we could extract dependencies at boot time. I don't like >>> the idea of adding a separate depends-on property because it is very >>> easy to get it out of sync with the actual binding data (dtc is not the >>> only tool that manipulates .dtbs. Firmware will fiddle with it too). >> >> >> Then that stuff has to fiddle correct. Sorry, but trying to solve all >> problems right from the beginning just leads to endless talks with no end >> and nothing will happen at all because nobody aggrees how to start. > > I appreciate the problem that you're trying to solve and why you're > using the dtc approach. My job is to poke at the solution and make > sure it is going to be reliable. Making sure all users know how to > fiddle with the new property correctly is not a trivial problem, > especially when it is firmware that will not necessarily be updated. The answer is just that they don't have to use this feature. It is more meant as a long-term solution to fix for the problem of increasing hard-coded workarounds which all are trying to fix the initialization order of drivers. Hardware has become a lot more complicated than it was in the good old days, and I think the time is right trying to adopt the init-system to this new century instead of still adding workarounds here and there. > I'm not saying flat out 'no' here, but before I merge anything, I have > to be reasonably certain that the feature is not going to represent a > maintenance nightmare over the long term. The maintenance nightmare is already present in form of all the workarounds which are trying to fix the initialzation order necessary for modern hardware. Regards, Alexander -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: holler@ahsoftware.de (Alexander Holler) Date: Wed, 14 May 2014 18:23:13 +0200 Subject: [RFC PATCH 0/9] dt: dependencies (for deterministic driver initialization order based on the DT) In-Reply-To: References: <1399913280-6915-1-git-send-email-holler@ahsoftware.de> <20140514141914.446F7C4153D@trevor.secretlab.ca> <53738580.7000902@ahsoftware.de> Message-ID: <53739871.9070407@ahsoftware.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Am 14.05.2014 18:05, schrieb Grant Likely: > On Wed, May 14, 2014 at 4:02 PM, Alexander Holler wrote: >> Am 14.05.2014 16:19, schrieb Grant Likely: >> >> >>> Rather than a dtb schema change, for the most common properties (irqs, >>> clocks, gpios), we could extract dependencies at boot time. I don't like >>> the idea of adding a separate depends-on property because it is very >>> easy to get it out of sync with the actual binding data (dtc is not the >>> only tool that manipulates .dtbs. Firmware will fiddle with it too). >> >> >> Then that stuff has to fiddle correct. Sorry, but trying to solve all >> problems right from the beginning just leads to endless talks with no end >> and nothing will happen at all because nobody aggrees how to start. > > I appreciate the problem that you're trying to solve and why you're > using the dtc approach. My job is to poke at the solution and make > sure it is going to be reliable. Making sure all users know how to > fiddle with the new property correctly is not a trivial problem, > especially when it is firmware that will not necessarily be updated. The answer is just that they don't have to use this feature. It is more meant as a long-term solution to fix for the problem of increasing hard-coded workarounds which all are trying to fix the initialization order of drivers. Hardware has become a lot more complicated than it was in the good old days, and I think the time is right trying to adopt the init-system to this new century instead of still adding workarounds here and there. > I'm not saying flat out 'no' here, but before I merge anything, I have > to be reasonably certain that the feature is not going to represent a > maintenance nightmare over the long term. The maintenance nightmare is already present in form of all the workarounds which are trying to fix the initialzation order necessary for modern hardware. Regards, Alexander