Heartbeat LED during init script

Heartbeat LED during init script

[barebox+mailing]

Hey everyone,

we use the barebox bootloader in on of our products.
Because of some norms we need to make a memtest of the RAM. To do that, we use the provided memtest tool.
So one of our our scripts is `/env/init/10-memtest`, which has just `memtest -tc` in it.


The other script is `/env/init/05-heartbeat` which contains 

#!/bin/sh

led -b board-red 100 1000

So, at first the 05 script is executed, afterwards the memtest script.

The problem is, that during the memtest the led does not blink, but flashes red the whole time. After the memtest is done, the blinking is done perfectly fine, but not during the memtest.

I create a small video to showcase this exact problem: https://imgur.com/a/9sxHTcm

Can anybody tell me why the barebox isn't able to keep up with the blinking as well as how to mitigate that?

Greetings,
Marcel

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Re: Heartbeat LED during init script

[Sascha Hauer]

On Wed, Feb 17, 2021 at 01:22:32PM +0100, barebox+mailing@cookiesoft.de wrote:
> Hey everyone,
> 
> we use the barebox bootloader in on of our products.
> Because of some norms we need to make a memtest of the RAM. To do that, we use the provided memtest tool.
> So one of our our scripts is `/env/init/10-memtest`, which has just `memtest -tc` in it.
> 
> 
> The other script is `/env/init/05-heartbeat` which contains 
> 
> #!/bin/sh
> 
> led -b board-red 100 1000
> 
> So, at first the 05 script is executed, afterwards the memtest script.
> 
> The problem is, that during the memtest the led does not blink, but flashes red the whole time. After the memtest is done, the blinking is done perfectly fine, but not during the memtest.
> 
> I create a small video to showcase this exact problem: https://imgur.com/a/9sxHTcm
> 
> Can anybody tell me why the barebox isn't able to keep up with the blinking as well as how to mitigate that?

barebox doesn't support interrupts. LED blinking is done in pollers,
that are little function that run each time a timing related function is
called. What you can do is to add for example add a ctrlc() call to your
memtester code inside some loop. That will cause the poller to run.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Heartbeat LED during init script

[barebox+mailing]

Hey Sasha,

thanks for the answer.

> barebox doesn't support interrupts. LED blinking is done in pollers

That explains the obversation.

> add a ctrlc() call to your memtester code inside some loop.
> That will cause the poller to run.

I'm not entirely sure, if I understand you correctly or you didn't understand me.

I use the memtest command[0] from barebox so there is nothing custom written or any loop that I can control.
However, if I understand you correctly one could add the `ctrlc` command in all of these[1] three loops inside the `mem_test_moving_inversions` function. Is that correct? Or is there an other way to not listen on ctrl+c but let the poller itself run?

Greetings,
Marcel

[0]: https://barebox.org/doc/latest/commands/mem/memtest.html
[1]: https://git.pengutronix.de/cgit/barebox/tree/common/memtest.c#n387

> Sascha Hauer <sha@pengutronix.de> hat am 17.02.2021 13:35 geschrieben:
> 
>  
> On Wed, Feb 17, 2021 at 01:22:32PM +0100, barebox+mailing@cookiesoft.de wrote:
> > Hey everyone,
> > 
> > we use the barebox bootloader in on of our products.
> > Because of some norms we need to make a memtest of the RAM. To do that, we use the provided memtest tool.
> > So one of our our scripts is `/env/init/10-memtest`, which has just `memtest -tc` in it.
> > 
> > 
> > The other script is `/env/init/05-heartbeat` which contains 
> > 
> > #!/bin/sh
> > 
> > led -b board-red 100 1000
> > 
> > So, at first the 05 script is executed, afterwards the memtest script.
> > 
> > The problem is, that during the memtest the led does not blink, but flashes red the whole time. After the memtest is done, the blinking is done perfectly fine, but not during the memtest.
> > 
> > I create a small video to showcase this exact problem: https://imgur.com/a/9sxHTcm
> > 
> > Can anybody tell me why the barebox isn't able to keep up with the blinking as well as how to mitigate that?
> 
> barebox doesn't support interrupts. LED blinking is done in pollers,
> that are little function that run each time a timing related function is
> called. What you can do is to add for example add a ctrlc() call to your
> memtester code inside some loop. That will cause the poller to run.
> 
> Sascha
> 
> -- 
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Heartbeat LED during init script

[Sascha Hauer]

On Wed, Feb 17, 2021 at 01:44:59PM +0100, barebox+mailing@cookiesoft.de wrote:
> Hey Sasha,
> 
> thanks for the answer.
> 
> > barebox doesn't support interrupts. LED blinking is done in pollers
> 
> That explains the obversation.
> 
> > add a ctrlc() call to your memtester code inside some loop.
> > That will cause the poller to run.
> 
> I'm not entirely sure, if I understand you correctly or you didn't understand me.
> 
> I use the memtest command[0] from barebox so there is nothing custom written or any loop that I can control.

Ok, somehow I thought you added some memtest code yourself. I was
mistaken.

> However, if I understand you correctly one could add the `ctrlc`
> command in all of these[1] three loops inside the
> `mem_test_moving_inversions` function. Is that correct? 

Yes, correct.

> Or is there an
> other way to not listen on ctrl+c but let the poller itself run?

You could add poller_call() directly. The idea of adding ctrlc() is just
that this way you could also make the memtest interruptible for the
user.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Heartbeat LED during init script

[Marcel Hellwig]

Hey Sasha,

I have a slight problem here:
This is what I think:

Because the memtest gets called in the init routine, the `ctrl` is completly ignored, at least I can't interrupt it nor the LED blinks.
But if I insert `poller_call`, the led blinks, but the memtest is painfully slow (like 10x slower at least).

I don't think that this will work for me, but I have to accept, that the LED doesn't blink while doing a memtest.

But an interruptable memtest would be nice at least for the user, so my patch I sent yesterday still remains ;)

Greetings,
Marcel

> Sascha Hauer <sha@pengutronix.de> hat am 17.02.2021 14:17 geschrieben:
> 
>  
> On Wed, Feb 17, 2021 at 01:44:59PM +0100, barebox+mailing@cookiesoft.de wrote:
> > Hey Sasha,
> > 
> > thanks for the answer.
> > 
> > > barebox doesn't support interrupts. LED blinking is done in pollers
> > 
> > That explains the obversation.
> > 
> > > add a ctrlc() call to your memtester code inside some loop.
> > > That will cause the poller to run.
> > 
> > I'm not entirely sure, if I understand you correctly or you didn't understand me.
> > 
> > I use the memtest command[0] from barebox so there is nothing custom written or any loop that I can control.
> 
> Ok, somehow I thought you added some memtest code yourself. I was
> mistaken.
> 
> > However, if I understand you correctly one could add the `ctrlc`
> > command in all of these[1] three loops inside the
> > `mem_test_moving_inversions` function. Is that correct? 
> 
> Yes, correct.
> 
> > Or is there an
> > other way to not listen on ctrl+c but let the poller itself run?
> 
> You could add poller_call() directly. The idea of adding ctrlc() is just
> that this way you could also make the memtest interruptible for the
> user.
> 
> Sascha
> 
> -- 
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Heartbeat LED during init script

[Sascha Hauer]

On Thu, Feb 18, 2021 at 09:00:42AM +0100, Marcel Hellwig wrote:
> Hey Sasha,
> 
> I have a slight problem here:
> This is what I think:
> 
> Because the memtest gets called in the init routine, the `ctrl` is
> completly ignored, at least I can't interrupt it nor the LED blinks.

Yes, ctrlc() is allowed only after startup. We could move calling
poller_call() up, before we test if ctrlc is allowed.

> But if I insert `poller_call`, the led blinks, but the memtest is
> painfully slow (like 10x slower at least).

poller_call() takes some time. A solution might be to call poller_call()
just every thousand times or so in memtest loop.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Heartbeat LED during init script

[Ahmad Fatoum]

Helo,

On 18.02.21 09:34, Sascha Hauer wrote:
> On Thu, Feb 18, 2021 at 09:00:42AM +0100, Marcel Hellwig wrote:
>> Hey Sasha,
>>
>> I have a slight problem here:
>> This is what I think:
>>
>> Because the memtest gets called in the init routine, the `ctrl` is
>> completly ignored, at least I can't interrupt it nor the LED blinks.
> 
> Yes, ctrlc() is allowed only after startup. We could move calling
> poller_call() up, before we test if ctrlc is allowed.

I believe that's the correct thing to do.
See my "[PATCH 2/3] console: unconditionally run poller_call in ctrlc()"
from a few days ago. You can cherry pick that now if you like.

> 
>> But if I insert `poller_call`, the led blinks, but the memtest is
>> painfully slow (like 10x slower at least).
> 
> poller_call() takes some time. A solution might be to call poller_call()
> just every thousand times or so in memtest loop.
> 
> Sascha
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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