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Date:   Mon, 5 Feb 2018 15:18:46 +0000
From:   Lina Iyer <ilina@codeaurora.org>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <marc.zyngier@arm.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm@vger.kernel.org, sboyd@codeaurora.org,
        rnayak@codeaurora.org, asathyak@codeaurora.org,
        Steven Rostedt <rostedt@goodmis.org>,
        Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH RFC v2 3/3] drivers: irqchip: pdc: log PDC info in FTRACE
Message-ID: <20180205151846.GA13552@codeaurora.org>
References: <20180202142200.6229-1-ilina@codeaurora.org>
 <20180202142200.6229-4-ilina@codeaurora.org>
 <alpine.DEB.2.21.1802021652100.1472@nanos.tec.linutronix.de>
 <20180202230232.GB15464@codeaurora.org>
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On Fri, Feb 02 2018 at 23:02 +0000, Lina Iyer wrote:
>On Fri, Feb 02 2018 at 15:57 +0000, Thomas Gleixner wrote:
>>On Fri, 2 Feb 2018, Lina Iyer wrote:
>>>+++ b/include/trace/events/pdc.h
>>>@@ -0,0 +1,55 @@
>>>+/* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>>>+ *
>>>+ * This program is free software; you can redistribute it and/or modify
>>>+ * it under the terms of the GNU General Public License version 2 and
>>>+ * only version 2 as published by the Free Software Foundation.
>>>+ *
>>>+ * This program is distributed in the hope that it will be useful,
>>>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>>+ * GNU General Public License for more details.
>>
>>Can you please use the proper SPDX identifiers instead of the boiler plate?
>>Same for the driver source file.
>>
>Sure.
>
>>>+ */
>>>+
>>>+#undef TRACE_SYSTEM
>>>+#define TRACE_SYSTEM pdc
>>>+
>>>+#if !defined(_TRACE_PDC_) || defined(TRACE_HEADER_MULTI_READ)
>>>+#define _TRACE_PDC_H_
>>>+
>>>+#include <linux/tracepoint.h>
>>>+
>>>+#define PDC_ENTRY		1
>>>+#define PDC_TYPE_CONFIG		2
>>>+
>>>+TRACE_EVENT(irq_pin_config,
>>
>>This is really a too generic name for a PDC specific breakpoint.
>>
>Hmm.. right.
>
>>Aside of that the question is whether this really justifies a trace
>>point. Wouldn't it be sufficient to use the GENERIC_IRQ_DEBUGFS
>>infrastructure to make this accessible via debugfs?
>>
>>
>Some product configurations disable debugfs. I will ask around if this
>can be dropped.
>
Memory dumps after a crash have support for FTRACE and it helps greatly
on production issues. Hence the preference for FTRACE support.

-- Lina