linux-pm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Lukasz Luba <lukasz.luba@arm.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: Mon, 3 Aug 2020 17:35:55 +0200	[thread overview]
Message-ID: <ceaa668e-a60b-1916-243b-145b1bc7fc76@samsung.com> (raw)
In-Reply-To: <db571467-48ec-8f11-de1d-00393d8aa99b@samsung.com>

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
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland


  reply	other threads:[~2020-08-03 15:36 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 [this message]
2020-08-04  8:06         ` Lukasz Luba
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ceaa668e-a60b-1916-243b-145b1bc7fc76@samsung.com \
    --to=m.szyprowski@samsung.com \
    --cc=b.zolnierkie@samsung.com \
    --cc=chanwoo@kernel.org \
    --cc=cw00.choi@samsung.com \
    --cc=k.konieczny@samsung.com \
    --cc=kgene@kernel.org \
    --cc=krzk@kernel.org \
    --cc=kyungmin.park@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=lukasz.luba@arm.com \
    --cc=myungjoo.ham@samsung.com \
    --cc=s.nawrocki@samsung.com \
    --cc=willy.mh.wolff.ml@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).