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 E5D9DC004D4 for ; Fri, 20 Jan 2023 00:53:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229781AbjATAx0 (ORCPT ); Thu, 19 Jan 2023 19:53:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229481AbjATAxY (ORCPT ); Thu, 19 Jan 2023 19:53:24 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1FAE9AAB9; Thu, 19 Jan 2023 16:53:21 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 17ABE514; Fri, 20 Jan 2023 01:53:17 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1674175998; bh=leFNSZshv+kpPN94K/far0pL9B7KIYKntxiaXNDjR4w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JXRMl3TludEwKOM8ACTPCGPZ4KXVAtKd4a3LEYyl3mTLrxbLqBhtSIZedlnTVXzYI R06RARw7I8Ajys8fEhQgvNMUnJWIqimdY5Ofi+CJS0/nTh7lw9mAiUKA8SrYT2UjgC x0wHKgEKCMqDg4UzmmyfJqIsRFssMHj5XFC41gI8= Date: Fri, 20 Jan 2023 02:53:15 +0200 From: Laurent Pinchart To: Dan Carpenter Cc: Phil Elwell , Greg Kroah-Hartman , Stefan Wahren , Umang Jain , linux-media@vger.kernel.org, linux-staging@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, Florian Fainelli , Adrien Thierry , Dave Stevenson , Kieran Bingham , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/4] Drop custom logging Message-ID: References: <20230118115810.21979-1-umang.jain@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2023 at 05:37:48PM +0300, Dan Carpenter wrote: > On Thu, Jan 19, 2023 at 02:31:50PM +0000, Phil Elwell wrote: > > On Thu, 19 Jan 2023 at 14:25, Dan Carpenter wrote: > > > On Thu, Jan 19, 2023 at 01:47:44PM +0000, Phil Elwell wrote: > > > > > > I understand the desire to remove the custom logging. I don't welcome > > > > > > the loss of flexibility that comes with such a strategy > > > > > > > > > > What "loss of flexibility"? You now have access to the full dynamic > > > > > debugging facilities that all of the rest of the kernel has. What is > > > > > lacking? > > > > > > > > Perhaps I've missed something, either in this patch set or the kernel > > > > as a whole, but how is one supposed to set different logging levels on > > > > different facilities within a driver/module, or even for the module as > > > > a whole? > > > > > > Yeah. You will be still able to do that and more besides after the > > > transition. Cleaning this up makes the code better in every way. > > > > > > Documentation/admin-guide/dynamic-debug-howto.rst > > > > Are you saying this patch set gets us to that point? > > Yes. The patch has some issues, but yes. I think I'm missing something too then. Dynamic debug provides the ability to easily switch dev_dbg() messages on and off at runtime, but it doesn't provide, as far as I'm aware, log levels or log categories. Log levels are currently used by the vchiq code to suppress messages below a certain level. Kernel log levels are not an exact replacement, as the messages still end up in the kernel log (except for debug messages). Log categories are used to group messages in categories and control their log level per category. As far as I know, dynamic debug doesn't provide any such feature. -- Regards, Laurent Pinchart