From: Pavel Machek <pavel@ucw.cz>
To: "Bollinger, Seth" <Seth.Bollinger@digi.com>
Cc: "linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>,
Dan Murphy <dmurphy@ti.com>, Seth Bollinger <seth.boll@gmail.com>
Subject: Re: Strange timer LED behavior
Date: Sat, 24 Oct 2020 09:45:17 +0200 [thread overview]
Message-ID: <20201024074516.GA32500@amd> (raw)
In-Reply-To: <6C8DDBC1-FCAF-411A-AA38-108CEE58EC9C@digi.com>
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On Thu 2020-10-22 11:34:34, Bollinger, Seth wrote:
>
> >>> Yeah. Don't do that! :-). For solid on/solid off, just turn the
> >>> trigger off. For blinking, use timer trigger.
> >>
> >> If I want to go from on or off to flashing, I need to set the timer trigger, which results in a 500 ms flash rate until the real rates are set. This results in a noticeably different first blink. I guess we’re looking for smooth control of the LED.
> >>
> >
> > Okay, that's fair requirement, I guess.
> >
> > If you have proposals how to solve this in a nice way, go ahead.
> >
> > As a hack...
> >
> > I believe you can go from on to off like this:
> >
> > on:9999,off:0 -> on:9999,off:1 -> on:1,off:9999 -> on:0,off:9999.
> >
> > (And I believe we should document this somewhere).
>
>
> I hate to respond to this, because it makes me look stupid, but… :)
>
> The problem turned out to be that the original author was using buffered IO to do the sysfs writes (which I didn’t notice until yesterday). When I switched to a different method, the writes were ordered correctly and didn’t glitch.
>
> Apologies for bothering you all, and great thanks for your assistance!
Hehe, okay. Good that it is solved.
(And yes, such bugs happen, forgetting about buffered i/o is quite
common).
Best regards,
Pavel
--
http://www.livejournal.com/~pavelmachek
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next prev parent reply other threads:[~2020-10-24 7:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 13:08 Strange timer LED behavior Bollinger, Seth
2020-10-19 14:06 ` Pavel Machek
2020-10-19 14:16 ` Bollinger, Seth
2020-10-20 12:04 ` Bollinger, Seth
2020-10-20 12:21 ` Pavel Machek
2020-10-20 12:31 ` Bollinger, Seth
2020-10-20 18:08 ` Pavel Machek
2020-10-20 18:28 ` Bollinger, Seth
2020-10-20 18:33 ` Pavel Machek
2020-10-20 18:35 ` Bollinger, Seth
2020-10-20 18:40 ` Pavel Machek
2020-10-20 18:51 ` Bollinger, Seth
2020-10-22 10:06 ` Pavel Machek
2020-10-22 11:34 ` Bollinger, Seth
2020-10-24 7:45 ` Pavel Machek [this message]
2020-10-21 20:23 ` Jacek Anaszewski
2020-10-22 11:35 ` Bollinger, Seth
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