From: Lukasz Luba <lukasz.luba@arm.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org
Cc: willy.mh.wolff.ml@gmail.com, k.konieczny@samsung.com,
cw00.choi@samsung.com, b.zolnierkie@samsung.com, krzk@kernel.org,
chanwoo@kernel.org, myungjoo.ham@samsung.com,
kyungmin.park@samsung.com, s.nawrocki@samsung.com,
kgene@kernel.org
Subject: Re: [PATCH v2 2/2] memory: samsung: exynos5422-dmc: Add module param to control IRQ mode
Date: Tue, 4 Aug 2020 09:06:01 +0100 [thread overview]
Message-ID: <92348c27-5c0e-56cc-82d5-9b22f190c7b3@arm.com> (raw)
In-Reply-To: <ceaa668e-a60b-1916-243b-145b1bc7fc76@samsung.com>
Hi Marek,
On 8/3/20 4:35 PM, Marek Szyprowski wrote:
> Hi All,
>
> On 03.08.2020 17:30, Marek Szyprowski wrote:
>> On 10.07.2020 21:11, Lukasz Luba wrote:
>>> The driver can operate in two modes relaying on devfreq monitoring
>>> mechanism which periodically checks the device status or it can use
>>> interrupts when they are provided by loaded Device Tree. The newly
>>> introduced module parameter can be used to choose between devfreq
>>> monitoring and internal interrupts without modifying the Device Tree.
>>> It also sets devfreq monitoring as default when the parameter is not set
>>> (also the case for default when the driver is not built as a module).
>>>
>>> Reported-by: Willy Wolff <willy.mh.wolff.ml@gmail.com>
>>> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
>>
>> I've got back from my holidays and noticed that in meantime this
>> commit got merged as commit 4fc9a0470d2d. It revealed that there is a
>> race between registering exynos5422-dmc driver and exynos-ppmu driver,
>> which can be observed sometimes as the following message and freeze on
>> Odroid XU3 with multi_v7_defconfig:
>>
>> [ 8.767708] exynos5-dmc 10c20000.memory-controller: couldn't probe
>> performance counters
>>
>> I will check this later why the EPROBE_DEFER error is not properly
>> propagated and why it causes a freeze.
>
> It looks that simply propagating return value from
> exynos5_counters_get() in exynos5_dmc_get_status() fixes the boot:
>
> # dmesg | grep dmc
> [ 8.838754] exynos-ppmu: new PPMU device registered 10d00000.ppmu
> (ppmu-event3-dmc0_0)
> [ 8.861344] exynos-ppmu: new PPMU device registered 10d10000.ppmu
> (ppmu-event3-dmc0_1)
> [ 8.868488] exynos5-dmc 10c20000.memory-controller: couldn't probe
> performance counters
> [ 8.874417] exynos-ppmu: new PPMU device registered 10d60000.ppmu
> (ppmu-event3-dmc1_0)
> [ 8.886612] exynos-ppmu: new PPMU device registered 10d70000.ppmu
> (ppmu-event3-dmc1_1)
> [ 9.396769] exynos5-dmc 10c20000.memory-controller: DMC initialized,
> in irq mode: 0
>
> I'm still curious why it freezes if getting performance counters is not
> possible.
>
> Best regards
>
Thank you for investigating this issue. Indeed, it's odd why it freezes.
I've seen you patch with the fix.
Regards,
Lukasz
next prev parent reply other threads:[~2020-08-04 8:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200710191144epcas1p30f82bf6371f7f09a4e1ea1262234f392@epcas1p3.samsung.com>
2020-07-10 19:11 ` [PATCH v2 0/2] Exynos5422 DMC: adjust to new devfreq monitoring mechanism Lukasz Luba
2020-07-10 19:11 ` [PATCH v2 1/2] memory: samsung: exynos5422-dmc: Adjust polling interval and uptreshold Lukasz Luba
2020-07-20 14:46 ` Krzysztof Kozlowski
2020-07-27 8:20 ` Lukasz Luba
2020-07-10 19:11 ` [PATCH v2 2/2] memory: samsung: exynos5422-dmc: Add module param to control IRQ mode Lukasz Luba
2020-07-14 7:42 ` Bartlomiej Zolnierkiewicz
2020-07-14 9:01 ` Lukasz Luba
2020-07-14 9:32 ` Willy Wolff
2020-07-14 9:50 ` Lukasz Luba
2020-07-17 11:53 ` Lukasz Luba
2020-07-17 12:31 ` Bartlomiej Zolnierkiewicz
2020-07-20 14:46 ` Krzysztof Kozlowski
2020-08-03 15:30 ` Marek Szyprowski
2020-08-03 15:35 ` Marek Szyprowski
2020-08-04 8:06 ` Lukasz Luba [this message]
2020-07-24 1:40 ` [PATCH v2 0/2] Exynos5422 DMC: adjust to new devfreq monitoring mechanism Chanwoo Choi
2020-07-27 8:21 ` Lukasz Luba
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