From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57BF4C04A68 for ; Wed, 27 Jul 2022 22:18:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235076AbiG0WSK (ORCPT ); Wed, 27 Jul 2022 18:18:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233525AbiG0WRu (ORCPT ); Wed, 27 Jul 2022 18:17:50 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8C72E7 for ; Wed, 27 Jul 2022 15:16:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=XvXJVy+rBpIQJ76z/DziDFa5OupRHVC9qObedvsCnsA=; b=jZHqO3FR97EkpZ9ambN5N9aUWH 5FSiv/oTs8VAwGfI6PKG0FTWesEdeHTk97YaL4nFFpXQRHJ3b4NcxVXTS2CzoJWGLwvS1WITpvUBc mNhdPQejhhDQcJYDC3Ql6XNAxZTJLL6QewzCj9tqxHvYBcJYqonDGZTJpumY/hLtmSV3kj2NEQFS5 IWmJjwuRw5HLJk7AYQfEwyrAnzqMF6sU24e6zPwn5/CL7mmGwnA7qQ+8lI7QnMyQmEubhX0rDRLMk aZJ/DgNOnUWXtb4ZO0M0MUnBdWkvSsyaoyd5D+VHdLTMpcVa83+qZyD4iXPM6Ri0QnExaKOeYA4Md PIULhafQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:33598) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1oGpKA-0005hS-A0; Wed, 27 Jul 2022 23:16:14 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1oGpK4-0002cD-Vm; Wed, 27 Jul 2022 23:16:08 +0100 Date: Wed, 27 Jul 2022 23:16:08 +0100 From: "Russell King (Oracle)" To: Saravana Kannan Cc: Philipp Zabel , Rob Herring , Ulf Hansson , Linus Walleij , Sudeep Holla , Nicolas Saenz Julienne , Geert Uytterhoeven , Marek Szyprowski , Kefeng Wang , Greg Kroah-Hartman , patches@armlinux.org.uk, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6] amba: Remove deferred device addition Message-ID: References: <20220727181936.3250466-1-saravanak@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220727181936.3250466-1-saravanak@google.com> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 27, 2022 at 11:19:35AM -0700, Saravana Kannan wrote: > The uevents generated for an amba device need PID and CID information > that's available only when the amba device is powered on, clocked and > out of reset. So, if those resources aren't available, the information > can't be read to generate the uevents. To workaround this requirement, > if the resources weren't available, the device addition was deferred and > retried periodically. > > However, this deferred addition retry isn't based on resources becoming > available. Instead, it's retried every 5 seconds and causes arbitrary > probe delays for amba devices and their consumers. > > Also, maintaining a separate deferred-probe like mechanism is > maintenance headache. > > With this commit, instead of deferring the device addition, we simply > defer the generation of uevents for the device and probing of the device > (because drivers needs PID and CID to match) until the PID and CID > information can be read. This allows us to delete all the amba specific > deferring code and also avoid the arbitrary probing delays. Oh, this is absolutely horrible. I can apply it cleanly to my "misc" branch, but it then conflicts when I re-merge my tree for the for-next thing (which is only supposed to be for sfr - the hint is in the name!) for-next is basically my "fixes" plus "misc" branch and anything else I want sfr to pick up for the -next tree. Applying this has to be on top of that merge commit, otherwise the conflicts are horrid, but that then means I need to send Linus the for-next merge commit (which I don't normally do.) Gah, we have too many changes to drivers/bus/amba.c in this cycle, some of them which have been submitted for 5.19 as fixes (and thus are not in 5.18-rc1 which the misc branch is based upon for other patch dependency reasons) and others in the misc branch for the next cycle - and now your patch wants both, which I can't do without rebasing the misc branch. Sadly, getting these changes into GregKH's tree will just create a conflict between Greg's tree and my tree. Can we postpone this please? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!