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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 B0544C07E85 for ; Fri, 7 Dec 2018 15:39:17 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82EC320672 for ; Fri, 7 Dec 2018 15:39:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="r+3Ak7Ak"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="euHSpLNq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82EC320672 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8NoORbyQ5bZxi1HR7P7QKESSxXxdYkftdVA/MAorXtA=; b=r+3Ak7AkW85RkT ZFJ1nUkMxTmcm7/bq8yI8+9OVtWeXAUHV+1XZisRXPgWRbxePWwaOF0CsXc2KwSM+yR0lJWTDO8Ok zP8D802mwdIU/yFpvYNGktGM++KXP77h3tL2sNGaUsQ5UunbkeY+1NecNvlNaCcS7+YV7ablNbVq1 CIgMMUcxQ1BbZtFBCAnG74gqaOAYo7moDzaZtsKFlC+6rQ4+fCvP8+qK46x5VtQqqxiZukFNMW0fz Y71u8nQqscYBjBh8vvSD/gIwGIrqq0ApVZnGjs8NW1+ahRLPqYTZZRokp0YgONzX04U8GzVuu5q3w piK8sWWTdoGQwSvC2zCw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVIDk-0003O3-Kc; Fri, 07 Dec 2018 15:39:16 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVIDh-0003Nb-RJ for linux-arm-kernel@lists.infradead.org; Fri, 07 Dec 2018 15:39:15 +0000 Received: from localhost (5356596B.cm-6-7b.dynamic.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 9E0E220672; Fri, 7 Dec 2018 15:39:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544197143; bh=dtP0TpUG4AYsA0L3w4YvqcC+JY7x9eY9bRkmjiW0ZJw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=euHSpLNq8owsZcV4aHsWfRVdt8HOkIWYcEiP0WItnJy+E4iU2O+Qq1YgKQim23BGp cZVsEQrPqPi7KjLfs09G4I9/YpOkolx7j6zzJjd6rBolIpi4Q4sMhrrMHw2HBniXk3 JNztdNyt8B/tI949p8Akw/7iRYpLIoC4A9i6tkvc= Date: Fri, 7 Dec 2018 16:39:01 +0100 From: Greg KH To: Thierry Reding Subject: Re: [PATCH v2 01/10] mailbox: Support blocking transfers in atomic context Message-ID: <20181207153901.GA29185@kroah.com> References: <20181112151853.29289-1-thierry.reding@gmail.com> <20181112151853.29289-2-thierry.reding@gmail.com> <0545f5e1-1740-2129-9d0e-5c950bd9bf74@nvidia.com> <20181129152312.GB23750@ulmo> <20181207113245.GA30719@ulmo> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20181207113245.GA30719@ulmo> User-Agent: Mutt/1.11.1 (2018-12-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181207_073913_897209_90E9F1DE X-CRM114-Status: GOOD ( 16.59 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Devicetree List , Jassi Brar , mliljeberg@nvidia.com, Mikko Perttunen , talho@nvidia.com, linux-serial@vger.kernel.org, jslaby@suse.com, linux-tegra@vger.kernel.org, ppessi@nvidia.com, Jon Hunter , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Dec 07, 2018 at 12:32:45PM +0100, Thierry Reding wrote: > Greg, > > any ideas on how we can move forward here? For reasons given elsewhere > in this thread I understand that there is no way to make the console > code run in non-atomic context. Have you ever run into a case where the > console driver couldn't busy-loop? Were there any solutions to this? I don't know of any such cases, hardware sucks at times, and we just have to deal with getting it to work by doing stuff like this :( > I've looked through quite a few drivers and they all end up with a busy > loop, waiting for the transmission FIFO to become empty. There are also > a few implementations for hypervisors that call back into some firmware > in order to send the characters, but I expect those to do the busy > looping in the firmware. busy loops are ok here, as you point out. > Perhaps the most prominent case that I came across and that is quite > similar to this discussion is netconsole. There's a lot of code in the > network layer that exists only to allow using a network device for > outputting a console. I don't think the changes to the mailbox > framework are anywhere near as complicated. Neither do I, I have no objection to your changes at all. thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel