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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 C3F0AC433E1 for ; Thu, 20 Aug 2020 14:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9F942075E for ; Thu, 20 Aug 2020 14:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727014AbgHTOVg (ORCPT ); Thu, 20 Aug 2020 10:21:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:52092 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725916AbgHTOVe (ORCPT ); Thu, 20 Aug 2020 10:21:34 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 CE15620738; Thu, 20 Aug 2020 14:21:32 +0000 (UTC) Date: Thu, 20 Aug 2020 10:21:31 -0400 From: Steven Rostedt To: Nicolas Boichat Cc: Mauro Carvalho Chehab , Greg Kroah-Hartman , Andy Gross , Bjorn Andersson , Todor Tomov , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: [PATCH v4 1/3, RESEND] media: camss: vfe: Use trace_printk for debugging only Message-ID: <20200820102131.3cd3c08e@oasis.local.home> In-Reply-To: <20200820170951.v4.1.Ia54fe801f246a0b0aee36fb1f3bfb0922a8842b0@changeid> References: <20200820170951.v4.1.Ia54fe801f246a0b0aee36fb1f3bfb0922a8842b0@changeid> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu, 20 Aug 2020 17:14:10 +0800 Nicolas Boichat wrote: > trace_printk should not be used in production code. Since > tracing interrupts is presumably latency sensitive, pr_dbg is > not appropriate, so guard the call with a preprocessor symbol > that can be defined for debugging purpose. > > Signed-off-by: Nicolas Boichat > --- > > (resending this patch as part of the whole series, since we need a new > patch 3/3 now). > > drivers/media/platform/qcom/camss/camss-vfe-4-1.c | 2 ++ > drivers/media/platform/qcom/camss/camss-vfe-4-7.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c > index 174a36be6f5d866..0c57171fae4f9e9 100644 > --- a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c > +++ b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c > @@ -936,8 +936,10 @@ static irqreturn_t vfe_isr(int irq, void *dev) > > vfe->ops->isr_read(vfe, &value0, &value1); > > +#ifdef CAMSS_VFE_TRACE_IRQ > trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n", > value0, value1); Why are these not trace events? The reason I have that ugly banner is to keep people from doing EXACTLY THIS! trace_printk() is really easy to add, but it also is not configurable. When a trace_printk() is in the code, it is always enabled (well, you can turn trace_printk off, but that's an all or nothing. That is, by turning trace_printk off, you turn off *all* trace_printks). Instead, people should add trace events. This here is a perfect place to have a trace event. You don't need to add #ifdef around trace events because when not enabled, they are simply a nop. When enabled, the nop is turned into a jump to the tracing code. It should not affect performance. And as a trace event, you get a bunch of features with it (filtering, histograms, etc). -- Steve > +#endif > > if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK) > vfe->isr_ops.reset_ack(vfe); > diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c > index 0dca8bf9281e774..307675925e5c779 100644 > --- a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c > +++ b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c > @@ -1058,8 +1058,10 @@ static irqreturn_t vfe_isr(int irq, void *dev) > > vfe->ops->isr_read(vfe, &value0, &value1); > > +#ifdef CAMSS_VFE_TRACE_IRQ > trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n", > value0, value1); > +#endif > > if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK) > vfe->isr_ops.reset_ack(vfe);