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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 D48F2C06513 for ; Wed, 3 Jul 2019 19:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A488521871 for ; Wed, 3 Jul 2019 19:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562182098; bh=4t35n7rE5OqFNPn1iMkzhdmrxUfUzfzBZpTy9xV2/gk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=tHJzZLItR1k5Zu9A5RheYtR2X6vuKprU0B4WaWepBpVEeuEn9SA0Uy3/6zamEiORJ uFEV6KuES9Zs9ujFXLqgJtNY/iUxstakud4Nn6p6UwqPDy3xngkxkzuiLhkoD0/XSJ vW9UDaxwe6FLMhJWfLlD0RFAg/gEpXKjAgjKublU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727008AbfGCT2R (ORCPT ); Wed, 3 Jul 2019 15:28:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:47524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726473AbfGCT2Q (ORCPT ); Wed, 3 Jul 2019 15:28:16 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 49B8620693; Wed, 3 Jul 2019 19:28:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562182095; bh=4t35n7rE5OqFNPn1iMkzhdmrxUfUzfzBZpTy9xV2/gk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QXV4hrZ5KCqsGLJSNC0aA2hvoam0DFeKfN8XneZg/8CBfmyKECAnwDUcLJ6EQrMg4 EY8Ib5UTEcI26QD96qx0sE6WDDaaQ7Uf6pXXX8QCBjBxToOMkcqU3c3wiNafF3Hb3G xWgiZ/i0qnG/F3uPqjOPCzG4WYwFY9XF8dLbbDfw= Date: Wed, 3 Jul 2019 21:28:13 +0200 From: Greg Kroah-Hartman To: Thierry Reding Cc: "Rafael J . Wysocki" , Linus Walleij , Rob Herring , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] driver: core: Allow subsystems to continue deferring probe Message-ID: <20190703192813.GA26808@kroah.com> References: <20190621151725.20414-1-thierry.reding@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190621151725.20414-1-thierry.reding@gmail.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 21, 2019 at 05:17:25PM +0200, Thierry Reding wrote: > From: Thierry Reding > > Some subsystems, such as pinctrl, allow continuing to defer probe > indefinitely. This is useful for devices that depend on resources > provided by devices that are only probed after the init stage. > > One example of this can be seen on Tegra, where the DPAUX hardware > contains pinmuxing controls for pins that it shares with an I2C > controller. The I2C controller is typically used for communication > with a monitor over HDMI (DDC). However, other instances of the I2C > controller are used to access system critical components, such as a > PMIC. The I2C controller driver will therefore usually be a builtin > driver, whereas the DPAUX driver is part of the display driver that > is loaded from a module to avoid bloating the kernel image with all > of the DRM/KMS subsystem. > > In this particular case the pins used by this I2C/DDC controller > become accessible very late in the boot process. However, since the > controller is only used in conjunction with display, that's not an > issue. > > Unfortunately the driver core currently outputs a warning message > when a device fails to get the pinctrl before the end of the init > stage. That can be confusing for the user because it may sound like > an unwanted error occurred, whereas it's really an expected and > harmless situation. > > In order to eliminate this warning, this patch allows callers of the > driver_deferred_probe_check_state() helper to specify that they want > to continue deferring probe, regardless of whether we're past the > init stage or not. All of the callers of that function are updated > for the new signature, but only the pinctrl subsystem passes a true > value in the new persist parameter if appropriate. > > Signed-off-by: Thierry Reding > Reviewed-by: Rafael J. Wysocki > Reviewed-by: Linus Walleij > --- > Changes in v3: > - add new function rather than extend the existing function with flags Much nicer, thanks for making the changes! greg k-h