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 EF8CAC433FE for ; Thu, 28 Apr 2022 05:51:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243209AbiD1FzE (ORCPT ); Thu, 28 Apr 2022 01:55:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233097AbiD1FzD (ORCPT ); Thu, 28 Apr 2022 01:55:03 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9F347C250; Wed, 27 Apr 2022 22:51:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 37F12B818FC; Thu, 28 Apr 2022 05:51:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DB6BC385A9; Thu, 28 Apr 2022 05:51:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651125106; bh=BL/ztcIdTOHAttqORil3BUGJFYSYBXhS93ayc6l+nXE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2rK9PWY7j41JX0nmeJkE6BBYRs1hKWOhGXMrtGRYSB8txFNFL3XlocI6+ubQ/O+8J t/DragmyB5XIeryU9mwNV9Fm0GJEA7fqErUp42mLVkCLZ8+SRzskjqgHOchg3WdaiK hLMSHBjS85b+PVwAFaAJJMJuu6PhU3Au1bOEGx5U= Date: Thu, 28 Apr 2022 07:51:39 +0200 From: Greg KH To: Sai Prakash Ranjan Cc: arnd@arndb.de, catalin.marinas@arm.com, rostedt@goodmis.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, maz@kernel.org, quic_psodagud@quicinc.com, quic_tsoni@quicinc.com, will@kernel.org Subject: Re: [PATCHv11 6/6] asm-generic/io: Add logging support for MMIO accessors Message-ID: References: <3de35c9f4a3a070d197bab499acefc709a6f5336.1645772606.git.quic_saipraka@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3de35c9f4a3a070d197bab499acefc709a6f5336.1645772606.git.quic_saipraka@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 28, 2022 at 09:00:13AM +0530, Sai Prakash Ranjan wrote: > Add logging support for MMIO high level accessors such as read{b,w,l,q} > and their relaxed versions to aid in debugging unexpected crashes/hangs > caused by the corresponding MMIO operation. Also add a generic flag > (__DISABLE_TRACE_MMIO__) which is used to disable MMIO tracing in nVHE KVM > and if required can be used to disable MMIO tracing for specific drivers. This "add a build flag to a Makefile to change how a driver operates" feels very wrong to me given that this is now a totally new way to control how a driver works at build time. That's not anything we have done before for drivers and if added, is only going to create much added complexity. How about requiring that the #define be in the .c files, and not in the Makefile, as Makefile changes are much much harder to notice and review over time. Also, I see that this "disable the trace" feature has already been asked for for 2 other drivers in the Android kernel tree, why not include those changes here as well? That kind of shows that this new feature is limited in that driver authors are already wanting it disabled, even before it is accepted. Because of that, who _will_ be using this feature? thanks, greg k-h