From: Pavel Machek <pavel@ucw.cz>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: linux-leds@vger.kernel.org, dmurphy@ti.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: ledtrig-cpu: Limit to 4 CPUs
Date: Tue, 22 Sep 2020 00:42:12 +0200 [thread overview]
Message-ID: <20200921224212.GA13299@amd> (raw)
In-Reply-To: <781dcb5e-7bad-f740-5914-778ec8a7306b@gmail.com>
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Hi!
> >Can I get details of your setup?
>
> I don't use this trigger, but I can imagine that someone does.
Well, if someone exists, we can increase the limit, or convince them
to change their setup.
> >What CPU type that is, and how are you mapping CPU activity to LEDs?
>
> The type of CPU is irrelevant here. What is important is the fact
> that with this trigger it is possible to visually monitor CPU core
> online state. Probably it would be good to ask the author of that
> trigger about his use case.
It is relevant -- cpu trigger never worked on x86. I had patch fixing
it, but got pushback.
> I have spoken up, because I don't get the reason for your patch.
> This driver was reworked year ago to remove PAGE_SIZE limit,
> and I even applied it to my for-next tree, but that was at
> the time of handling maintainership to yourself, and you
> seem to not have picked that commit.
>
> Was that intentional? We had even Greg's ack [0].
I checked, and I believe the commit is in:
#ifdef CONFIG_LEDS_TRIGGERS
static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write,
0);
static struct bin_attribute *led_trigger_bin_attrs[] = {
So.. no, it is not causing kernel crashes or something. But it is
example of bad interface, and _that_ is causing problems. (And yes, if
I realized it is simply possible to limit it, maybe the BIN_ATTR
conversion would not be neccessary...)
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2020-09-21 22:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 9:38 ledtrig-cpu: Limit to 4 CPUs Pavel Machek
2020-09-20 14:15 ` Jacek Anaszewski
2020-09-20 15:39 ` Marek Behun
2020-09-20 16:55 ` Jacek Anaszewski
2020-09-20 17:33 ` Marek Behun
2020-09-20 17:49 ` Jacek Anaszewski
2020-09-20 18:34 ` Pavel Machek
2020-09-21 22:14 ` Jacek Anaszewski
2020-09-21 22:42 ` Pavel Machek [this message]
2020-09-22 20:41 ` Jacek Anaszewski
2020-09-25 8:51 ` Jacek Anaszewski
2020-09-25 9:40 ` Pavel Machek
2020-09-26 13:59 ` Jacek Anaszewski
2020-10-08 10:10 ` Pavel Machek
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