From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1516878088; cv=none; d=google.com; s=arc-20160816; b=K6QBKm1Mn3k8MDjAV9A16sn4SAm6p31aZOnVLIEK+oZY8WbW0tsmIe8rNLR9i0iqB4 Z1V2+4kE6l2Xz6yKSbgYKIkcv6rDbfCXZkDtm0wHg/PSihL3b75Da5Wal/xAAeuMQZXA qH63rhS5CuXv46taCpZsUtf3g1mSUALo4uE95OjFE4pyQ/9BB3g9WENS60kcVthymKX+ pKtz2IE9YNXbUUaRrTm8JUxGCd6xyhvGD0+UY7bvmy6Jd+xsaszZH0bbr7+40jvISidu 3Gd5DLcWymJBbXhynNd0XiOAlCBAoThT2h0Kms8H5N0pFzy3cmvKcGerWEe+U+7Ig5oV Uryw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=MkWGxS0Q2VtmGW59h4vJnkbDcqFWgvpXgboBR+wNpMM=; b=vV/vP2fp1+f7l0L8RKqRoIStvL5LDc1tMW2dFoBsKZlMEyp4QIGgA+1LMcGBsziiwa yPTggxeMHptpaN21enXU+Xk7QGJC0tR7FED9o1Ks2EIwfT7Mh6vfQMKmoHx/2/FAcGDd 1/KHQjT+SXeb2G7gd4dh6onF4PV9xl9mK80ls2ROQUYjt6/WdT27fuLUqYNFGMrKxlzU tiBGBZNsMPGDhXtGcC2ZpkhnVeUyd4FsHszfEVOq/a+4OfJgU+tM1VwwtX5Wxob21Xe+ 9SNdFmX8bYsY6m0F6gFm0hmEtswj350QopHTVBd9ddsH/WfR2rrIHqkRxWNv5Qwnwp3O OJBg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=Kt+G8DqU; spf=pass (google.com: domain of viresh.kumar@linaro.org designates 209.85.220.41 as permitted sender) smtp.mailfrom=viresh.kumar@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=Kt+G8DqU; spf=pass (google.com: domain of viresh.kumar@linaro.org designates 209.85.220.41 as permitted sender) smtp.mailfrom=viresh.kumar@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org X-Google-Smtp-Source: AH8x225KGhdDCECyRanEIw27V4Ik9F2zB9E4I+OZyLQ7QuAhizDgplz8Tb68hcYXv6Y1/RU7622vAw== Date: Thu, 25 Jan 2018 16:31:25 +0530 From: Viresh Kumar To: Rob Herring Cc: Greg Kroah-Hartman , Vincent Guittot , Stephen Boyd , Rajendra Nayak , "linux-kernel@vger.kernel.org" , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , Rob Clark , Sascha Hauer , Lucas Stach , Shawn Guo , Fabio Estevam , Nishanth Menon , Wei Xu Subject: Re: [PATCH V6 Resend 00/13] drivers: Boot Constraint core Message-ID: <20180125110125.GA3307@vireshk-i7> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1586774022832035063?= X-GMAIL-MSGID: =?utf-8?q?1590561959098665734?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 10-01-18, 17:13, Rob Herring wrote: > On Tue, Jan 9, 2018 at 9:47 PM, Viresh Kumar wrote: > > A typical example of that can be the LCD controller, which is used by > > the bootloaders to show image(s) while the platform is booting into > > Linux. The LCD controller can be using some resources, like clk, > > regulators, etc, that are shared between several devices. These shared > > resources should be configured to satisfy need of all the users. If > > another device's (X) driver gets probed before the LCD controller driver > > in this case, then it may end up disabling or reconfiguring these > > resources to ranges satisfying the current users (only device X) and > > that can make the LCD screen unstable. > > We already have simple fb and a binding for it. It only handles clocks > I think, but could be extended to other things. I rather not extend > it, but it is there already and we don't need different solutions for > this. Got a bit busy lately and wasn't able to look into the details of it. So AFAICT the basic problem I was trying to solve still exists with simple-fb as well. And the problem is that nothing prevents another driver to get probed before the display driver (or simple-fb) and reconfigure the resources. Even if we let simple-fb come up really early, the resources like clk/regulator may not be available. And so the ordering thing is still unsolved for me. -- viresh