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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBBA1C4363C for ; Sun, 4 Oct 2020 14:10:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6782020735 for ; Sun, 4 Oct 2020 14:10:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=walle.cc header.i=@walle.cc header.b="bxjyZbK6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725907AbgJDOKt (ORCPT ); Sun, 4 Oct 2020 10:10:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725825AbgJDOKt (ORCPT ); Sun, 4 Oct 2020 10:10:49 -0400 Received: from ssl.serverraum.org (ssl.serverraum.org [IPv6:2a01:4f8:151:8464::1:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E23ECC0613CE for ; Sun, 4 Oct 2020 07:10:48 -0700 (PDT) Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 5EC4022EDE; Sun, 4 Oct 2020 16:10:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1601820647; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xVT1+uHV60x1aVCZ95DvmbILFkWAS7anVazJ1b7EIoQ=; b=bxjyZbK6MEBzL6yVKoDx8aHhT0lKMZgS8k28EDwu4jzwfjSz9EgVO8yaOQ9xd5pwL0MLXF SozTiDFIWc06BrLqCfdvkzaB7gPFuJJ5KlTAOaJbY07+8dGVGEP/DWriD4Sx7PJMCsrdXq H/7bdvJ4zxTVXy/g/w16ekHa98GQytQ= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Sun, 04 Oct 2020 16:10:46 +0200 From: Michael Walle To: Doug Anderson Cc: LKML , linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com, richard@nod.at, tudor.ambarus@microchip.com, vigneshr@ti.com Subject: Re: [PATCH] mtd: spi-nor: Prefer asynchronous probe In-Reply-To: References: <20200902160002.1.I658d1c0db9adfeb9a59bc55e96a19e192c959e55@changeid> <20201003150633.23416-1-michael@walle.cc> User-Agent: Roundcube Webmail/1.4.8 Message-ID: <23aa87ccb6ae4133a17885b809194161@walle.cc> X-Sender: michael@walle.cc Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Am 2020-10-03 19:00, schrieb Doug Anderson: > On Sat, Oct 3, 2020 at 9:54 AM Michael Walle wrote: >> While debugging another issue I also noticed that sometimes my >> /dev/mtdN devices were reordered. Note that I have two SPI flashes. >> Might this also be connected to the async probe? > > It's likely. My guess is that you shouldn't really be depending on > the numbering. If you need to depend on the numbering, there should > be something that guarantees it like a device tree alias. We have > struggled with similar things on MMC for years and I guess Ulf finally > decided that we weren't going to get a better solution than the device > tree aliases. But this has to be supported by spi-nor first, right? So that would also be something which has to be added before we can make the probe async. And as far as I know there is no such mechanism like /dev/disk/by-X for /dev/mtdN. -michael