From patchwork Thu Jan 2 22:07:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 234658 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 E603DC3276E for ; Thu, 2 Jan 2020 22:41:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8EB521835 for ; Thu, 2 Jan 2020 22:41:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004898; bh=0Dblhok8bPA/sWIxPAeAa083kIyZzTF6dnuS/BlAs2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NmvQJs2H6NAR+fJnJLc8MffVJpebEfQWdrwci0pCFtkpRKwSJTVeB9nZKhhyAVTaT pUeNG3+rTkiE2i1QKm2G4U812no9WPRvlxDd29it6DX8EoZjZ80gDPsFT3AyzO01i/ IUkB7vWDMT839vjjhj4fngYg4X4QDy8LPccm4tSA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730757AbgABWg5 (ORCPT ); Thu, 2 Jan 2020 17:36:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:48752 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731025AbgABWg5 (ORCPT ); Thu, 2 Jan 2020 17:36:57 -0500 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 7DF9921835; Thu, 2 Jan 2020 22:36:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004617; bh=0Dblhok8bPA/sWIxPAeAa083kIyZzTF6dnuS/BlAs2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fIn+25JbsvRMj6MfssXjArT0WTqB+F7I56l1Y0Fm3dK1EP/PDymZpC7efkazEuZfT NMfdnw3DG47U09qHYFkygNVynbtQVElh8O5AdEtoCr0Hr5WU68hTKvNRcIUgPIVnh+ AogLFgD8C2LxutB2VCIWUhOxvR/wDBL0ODU1xw28= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sudip Mukherjee , Sasha Levin Subject: [PATCH 4.4 055/137] parport: load lowlevel driver if ports not found Date: Thu, 2 Jan 2020 23:07:08 +0100 Message-Id: <20200102220553.948985356@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220546.618583146@linuxfoundation.org> References: <20200102220546.618583146@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sudip Mukherjee [ Upstream commit 231ec2f24dad18d021b361045bbd618ba62a274e ] Usually all the distro will load the parport low level driver as part of their initialization. But we can get into a situation where all the parallel port drivers are built as module and we unload all the modules at a later time. Then if we just do "modprobe parport" it will only load the parport module and will not load the low level driver which will actually register the ports. So, check the bus if there is any parport registered, if not, load the low level driver. We can get into the above situation with all distro but only Suse has setup the alias for "parport_lowlevel" and so it only works in Suse. Users of Debian based distro will need to load the lowlevel module manually. Signed-off-by: Sudip Mukherjee Link: https://lore.kernel.org/r/20191016144540.18810-3-sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/parport/share.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/parport/share.c b/drivers/parport/share.c index f26af0214ab3..3be1f4a041d4 100644 --- a/drivers/parport/share.c +++ b/drivers/parport/share.c @@ -228,6 +228,18 @@ static int port_check(struct device *dev, void *dev_drv) return 0; } +/* + * Iterates through all the devices connected to the bus and return 1 + * if the device is a parallel port. + */ + +static int port_detect(struct device *dev, void *dev_drv) +{ + if (is_parport(dev)) + return 1; + return 0; +} + /** * parport_register_driver - register a parallel port device driver * @drv: structure describing the driver @@ -280,6 +292,15 @@ int __parport_register_driver(struct parport_driver *drv, struct module *owner, if (ret) return ret; + /* + * check if bus has any parallel port registered, if + * none is found then load the lowlevel driver. + */ + ret = bus_for_each_dev(&parport_bus_type, NULL, NULL, + port_detect); + if (!ret) + get_lowlevel_driver(); + mutex_lock(®istration_lock); if (drv->match_port) bus_for_each_dev(&parport_bus_type, NULL, drv,