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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Leo Yan <leo.yan@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	James Clark <james.clark@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH v2 9/9] coresight: Refactor runtime PM
Date: Wed, 7 May 2025 11:09:24 +0530	[thread overview]
Message-ID: <b6774c27-0628-46d8-a186-bfd378ee538f@arm.com> (raw)
In-Reply-To: <20250506101604.GD177796@e132581.arm.com>



On 5/6/25 15:46, Leo Yan wrote:
> On Fri, May 02, 2025 at 02:15:49PM +0530, Anshuman Khandual wrote:
>>
>> On 4/23/25 20:47, Leo Yan wrote:
>>> The validation for driver data pointers and clock pointers are redundant
>>> in the runtime PM callbacks.  After a driver's probing, its driver data
>>> and clocks have been initialized successfully, this ensures it is safe
>>> to access driver data and clocks in the runtime PM callbacks.  A corner
>>> case is a clock pointer is NULL, in this case, the clock core layer can
>>> handle it properly.  So remove these redundant checking.
>>>
>>> In runtime resume, respect values returned from clock function and add
>>> error handling.
>>
>> Although not checking drvdata and drvdata->apb_clk does make sense, but
>> why change the semantics on the resume paths as well, which now returns
>> stored error value from clk_prepare_enable().
> 
> Let us assume if a clock fails to enable during the resume flow, with
> current code, we miss a chance to detect issues in the first place.
> 
> I understand the clock enabling failures are rare, but propagating an
> error in the resume callbacks would help identify potential issues.
> 
> It seems to me that this patch does not change the semantics of the
> resume paths.  It enhances the resume flow for early error reporting.

Alright, fair enough.

      reply	other threads:[~2025-05-07  5:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-23 15:17 [PATCH v2 0/9] coresight: Fix and improve clock usage Leo Yan
2025-04-23 15:17 ` [PATCH v2 1/9] coresight: tmc: Support atclk Leo Yan
2025-04-23 15:17 ` [PATCH v2 2/9] coresight: catu: " Leo Yan
2025-04-23 15:17 ` [PATCH v2 3/9] coresight: etm4x: " Leo Yan
2025-04-23 15:17 ` [PATCH v2 4/9] coresight: Disable programming clock properly Leo Yan
2025-05-02  6:10   ` Anshuman Khandual
2025-05-06  9:54     ` Leo Yan
2025-05-07  5:59       ` Anshuman Khandual
2025-04-23 15:17 ` [PATCH v2 5/9] coresight: Disable trace bus " Leo Yan
2025-05-02  6:31   ` Anshuman Khandual
2025-04-23 15:17 ` [PATCH v2 6/9] coresight: Avoid enable programming clock duplicately Leo Yan
2025-05-02  6:38   ` Anshuman Khandual
2025-05-06  9:18     ` Leo Yan
2025-05-07  5:55       ` Anshuman Khandual
2025-04-23 15:17 ` [PATCH v2 7/9] coresight: Consolidate clock enabling Leo Yan
2025-05-05  7:28   ` Anshuman Khandual
2025-05-06 10:53     ` Leo Yan
2025-05-07  5:51       ` Anshuman Khandual
2025-04-23 15:17 ` [PATCH v2 8/9] coresight: Make clock sequence consistent Leo Yan
2025-05-02  6:56   ` Anshuman Khandual
2025-04-23 15:17 ` [PATCH v2 9/9] coresight: Refactor runtime PM Leo Yan
2025-05-02  8:45   ` Anshuman Khandual
2025-05-06 10:16     ` Leo Yan
2025-05-07  5:39       ` Anshuman Khandual [this message]

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