dom
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Re: config.txt

Tue Feb 14, 2012 12:27 am

You need root privileges to write to boot partition.

There is no overvoltage/overclock setting that will instantly fry the device.

How about I add a config.txt setting

never_overvoltage=1

You boot once with that, it sets an OTP bit. You'll then never ever be allowed to overvoltage your chip, hence you can't void your warranty that way.

Would that satisfy you?

nelson
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Re: config.txt

Tue Feb 14, 2012 1:11 am

That seems nice from the IT point of view but from the legal/warranty point of view it may create problems for the foundation with people complaining that their pi is damaged as they can't overclock. better seek some legal advice.

Docteh
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Re: config.txt

Tue Feb 14, 2012 1:34 am

Especially since it"s a FAT partition, if voiding the warranty is a real option, the Foundation should make sure that the partition not mounted read/write by default in any default image. At least root privligees would/should be needed to void someones warranty.

But yes, that remains a good point. I can"t see a solution, and I"m kind of stuck between agreeing with the issue and the position of "if they"re executing stuff with full privileges, they own the hardware anyway". I don"t think that is a very friendly option, but it does have a point...

(Apologies for typo"s, the letters appear about 15 seconds after being typed, and I can"t spell check it all afterwards.)

My crazy idea for this is to use a file with a serial number in the filename eg 1727177243.txt for options like allow overclock/disallow overclock

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kyndair
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Re: config.txt

Tue Feb 14, 2012 2:42 am

dom said:


You need root privileges to write to boot partition.

There is no overvoltage/overclock setting that will instantly fry the device.

How about I add a config.txt setting

never_overvoltage=1

You boot once with that, it sets an OTP bit. You'll then never ever be allowed to overvoltage your chip, hence you can't void your warranty that way.

Would that satisfy you?



Hi Dom

I think it would be best to keep it simple and allow people to modify. If the defaults were included along with something like #raising the voltage above the default will void the warranty, only change if you know what you're doing. just above the setting people can't claim they weren't told. In the classroom environment root access should not be possible so it should not be an issue.

This along with a warning in the manual and on the wiki would be sufficient it also avoids the problem envisioned by Nelson of people complaining for the oppistae reason as they did not alter the config.txt prior to first boot.

Jonothan

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Jessie
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Re: config.txt

Tue Feb 14, 2012 3:57 am

I don't see an issue here.  Default distro images arn't going to come with the device set to overclock and overvolt.  Pretty much you can just tell people that if they arn't running the supported distro downloaded from an officail link that there is no gaurantee that their device hasn't been overvolted and had it's warranty voided.

Anyone, haphazardly downloading images and running them should know better.  You can put all the fail-safes you want but someone is still going to ruin one and claim that no one told them about the over-volting ruining their warranty.  I suppose by doing a little of this and that you can claim that you have done your due-dillegence.

I can gaurantee that the first one I get will have all kinds of warranty voiding mods done to it.  Connectors cut off, overclocked, and if it gets even slightly warm it will have a heatsink glued to it.  The final point I have here is that I doubt that even with over-volting and overclocking it will be easy to break one of these, someone could prove me wrong but I bet it will just fail to load before it burns up.

HeadCase
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Re: config.txt

Tue Feb 14, 2012 6:05 am

My understanding of this Overvolt Flag problem is that if a RPi board is left unattended, someone could insert a "bad" SD card with out of spec settings, power-cycle the board and reboot, then replace the original SD CARD.  Warranty voided.

Does each RPi have a unique public ID string (like a serial number) accessible?

If so, then a solution would be to qualify the risky config.txt options with the ID string included in the file. That would mean that to do things like overvolting, the config.txt file would have to be explicitly modified for that RPi. Without the ID, generic options would work as normal.

khulat
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Re: config.txt

Tue Feb 14, 2012 8:02 am

Well i don't see a big problem here, since there are easier and cheaper ways to void the warranty of a Pi. A key, or pocket knife are probably all the "tools" you need to do that.

Maybe we should not worry too much about malicious people that want to destroy the warranty of other people because they will find a way no matter what.

As long as it's stated clearly in the config file that overvolting voids your warranty, that should be enough. Combined with the warning to only use official downloads of course.

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RaTTuS
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Re: config.txt

Tue Feb 14, 2012 9:00 am

id number or MAC address as the .config file ?
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NAB
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Re: config.txt

Tue Feb 14, 2012 9:16 am

khulat said:


Well i don't see a big problem here, since there are easier and cheaper ways to void the warranty of a Pi. A key, or pocket knife are probably all the "tools" you need to do that.

Maybe we should not worry too much about malicious people that want to destroy the warranty of other people because they will find a way no matter what.


Which is absolutely fine for one person buying and using one RPi. However, that is not the stated intention of the device - namely to introduce kids to programming.

Given that (assuming the project is successful), the vast majority of these boards will be in schools being played with by kids and kids being what they are, I can pretty much guarantee that the first thing the kids will do is overvoltage the unit (whether out of maliciousness, mischief or just plain "I want it to run faster").

I really can't see the need of this 'feature' in the device at all - it's not something that will be used by the device's target audience and the very fact that it's there could cause that target audience some problems.

As for the "Well, it's your fault, you downloaded that image." - How long would it take one kid to insert an SD card and reboot every device owned by a school?

Personally, I like the idea of having the 'never overvoltage' switch, however this requires specific knowledge and deliberate action by the device owners. I also like the idea of needing to use a serial number to enable the feature - it means that one SD image cannot just be used on multiple devices, it must be hand-crafted.

So I say both - permit the permanent disablement of the feature and also ensure that if the feature is requested, the request is specific to the board in question.

Nicholas

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Re: config.txt

Tue Feb 14, 2012 9:43 am

I think you are overestimating the impact of "only" 1,4 V Max. The chip is at 1,2 volts as default which is already pretty close to that.

It's not with only 1,4 V that you will destroy the device.

One idea should be to have this never allow overvolting bit. And make it on by default on Schools Raspberries. Making School Raspberries resistant to that parameter and never voiding the warranty that way.

But I don't know why you are voiding the warranty for only 1,4 V Is there really any huge risks of failure ? If it is really the case, making the maximum 1,3 V and bye the warranty bit. Because theses chips are not that easy to kill AFAIK. If an overheating protection is on the chip I don't know what wrong could append in the warranty time (because yes I don't know what will be the warranty but I don't think it will be 3 years)

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Re: config.txt

Tue Feb 14, 2012 9:47 am

HDMI_CEA_480p60H         =  3,

HDMI_CEA_480i60_4x       = 10,

HDMI_CEA_480i60_4xH      = 11,

HDMI_CEA_480p60_2x       = 14,

HDMI_CEA_480p60_2xH

I'm confused to what the above video modes are, what does a plain 60 stand for in comaprison to 60H, also what is _4xH, _4x and _2x, _2xH.

Regards,

Jack.

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kyndair
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Re: config.txt

Tue Feb 14, 2012 9:54 am

To modify my earlier suggestion, include the non overclock statement in the config commented out, with a comment next to it saying that if it is uncommented the board wil not be capable of being overclocked in the future, this will allow school techs setting up the schools equipment to set the otp bit for the school equipment.

I work as technologist in retail developing products so dealing with customer issues with products is something I have deal with when designing products (including warning labels and manuals) and dealing the fallout when we get it wrong and the customer just doesn't get it. The first rule to learn is that it must be assumed the customer does not know anything about using the product but is intelligent enough to learn but lazy enough not to rtfm, hence the suggested comments in the config.txt.

Jonothan

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Re: config.txt

Tue Feb 14, 2012 10:05 am

kyndair said:

...hence the suggested comments in the config.txt.
But again, that will work for one person, one board. That approach will not work in a hostile environment where the board is owned by person A (e.g. a school) and used by persons B through Z (the pupils).

If overvoltaging the board is so dangerous to the device that using it voids the warranty (and shortens the life of the device), then the board owners need to have some protection against that, and that protection needs to be installed from the word go and require no intervention from them.

Of course, if overvoltaging the device isn't that dangerous, then don't void the warranty if somebody does it.

Nicholas.

khulat
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Re: config.txt

Tue Feb 14, 2012 10:09 am

NAB said:

Which is absolutely fine for one person buying and using one RPi. However, that is not the stated intention of the device - namely to introduce kids to programming.
Given that (assuming the project is successful), the vast majority of these boards will be in schools being played with by kids and kids being what they are, I can pretty much guarantee that the first thing the kids will do is overvoltage the unit (whether out of maliciousness, mischief or just plain "I want it to run faster").

I really can't see the need of this 'feature' in the device at all - it's not something that will be used by the device's target audience and the very fact that it's there could cause that target audience some problems.

As for the "Well, it's your fault, you downloaded that image." - How long would it take one kid to insert an SD card and reboot every device owned by a school?

Personally, I like the idea of having the 'never overvoltage' switch, however this requires specific knowledge and deliberate action by the device owners. I also like the idea of needing to use a serial number to enable the feature - it means that one SD image cannot just be used on multiple devices, it must be hand-crafted.

So I say both - permit the permanent disablement of the feature and also ensure that if the feature is requested, the request is specific to the board in question.

Nicholas



Well as i said if you include maliciousness and mischief there are plenty ways to vandalize anything. The "I want it to run faster" is of course a valid concern, but as you would need root access or another sd card i think it should'nt be as big a problem as you seem to think it is.

Maybe it's just me but i think being paranoid about kids destroying everything is not the right aproach to take. But that is more of a sociological problem, and offtopic.

The switch to disable overvolting would probably be the best compromise if it is easy to implement.

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Re: config.txt

Tue Feb 14, 2012 10:45 am

One way to avoid overvolting (is that really a word?) may be to ensure that only 5V power supplies are available in the classroom (and even glue them to the 'Pi? - although that too might void the warranty). Another is to charge anybody who does try it for the cost of the fried 'Pi. One key factor in a computer at this price point is that they are almost disposable items, and whilst I hate to see any 'Pi suffer in this way, can be replaced relatively easily and cheaply.

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kyndair
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Re: config.txt

Tue Feb 14, 2012 10:49 am

NAB said:

But again, that will work for one person, one board. That approach will not work in a hostile environment ...

Not really, a school could have a standard image that they deploy with the that permanently sets the no overvoltage bit so if the student replaces the card without being noticed it makes no difference.

Moving from 1.2 to 1.4 while not large numerical, increase it is a 17% increase and will shorten the life of the chip and could bring you into the the area where manufacturing tolerances are a significant problem and the the chip could fail v. quickly e.g. if the tolerance is 20% that would an average not the minimum and it probably would vary between 18% & 22% at the size the chips are printed at a few atoms out either way in the wrong place can make a difference between one persons success at oc'ing and anther complaining that they have a flaky pi

Now if you'll excuse the talk of flaky pi is getting me hungry

jamesh
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Re: config.txt

Tue Feb 14, 2012 10:51 am

I used to work for a company that made industrial ink jet printers - the sort on production lines that put on best before date etc. Interesting tech, and we also made ones that printed white ink - quite complicated as that's a colloidal ink  so need constant stiring.

Anyway, some of these white ink printers went on a milk production line.

I think you may see where this is going. The workers, when they fancied some time off, deliberately put milk in to the printer instead of ink (Der, it's all white innit?). This very effectively takes the machine out of action for some hours to be flushed and reinstalled. Whilst machine is offline, production line stops.

That's what you have to deal with in the real world. Deliberate sabotage (and very expensive sabotage at that)., And these are adults.
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Re: config.txt

Tue Feb 14, 2012 11:15 am

khulat said:

but as you would need root access or another sd card i think it should'nt be as big a problem as you seem to think it is.
Nope. All you need to do is take the SD card out, put it in a Windows machine and create/edit the config.txt file.


Maybe it's just me but i think being paranoid about kids destroying everything is not the right aproach to take. But that is more of a sociological problem, and offtopic.


I think you are completely misunderstanding my point. Yes, kids will try everything they can and the best learning is always better when it's done through making mistakes. I am not being paranoid about kids destroying everything.

However... What I am talking about is an easy, deliberate and invisible way a board can have its warranty disabled. This means that if there is a fault on the board, I have to throw the board away and buy another.

With this option available in config.txt, the foundation would effectively be saying to schools "Yes, you can buy 100, but be aware there's no warranty.". Now you and I know that that doesn't matter much, but tell the average school bursar or parent that they need to spend some money on something that comes with no warranty.


The switch to disable overvolting would probably be the best compromise if it is easy to implement.


Then there would need to be a piece of paper sent out with every single RPi which says "Warning - to ensure your warranty is not voided, download this image (link), put it on an SD and boot the RPi with it in once." - if not, how would people know to flip the switch?

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Re: config.txt

Tue Feb 14, 2012 11:27 am

JamesH said:


That's what you have to deal with in the real world. Deliberate sabotage (and very expensive sabotage at that)., And these are adults.


Kids are good at the non-deliberate sabotage too.

There is the story of the pupils that had learned that if you bang the black-board eraser next to the fan, an amusing cloud of chalk dust flew out of the drive bays.

When my mother worked in the nursery department I was called to fix a PC that had a floppy drive that nothing could be inserted into. I removed the drive, eased off the tin lid, and removed two two-pence pieces and Barbie's handbag.

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Re: config.txt

Tue Feb 14, 2012 11:44 am

kyndair said:


To modify my earlier suggestion, include the non overclock statement in the config commented out, with a comment next to it saying that if it is uncommented the board wil not be capable of being overclocked in the future, this will allow school techs setting up the schools equipment to set the otp bit for the school equipment.


No. Because a pupil could bring his own RaspPi into school, insert the school's SD card for his lesson, and then never be able to overvolt his card again. You can tell them not to set the bit on all card images, but I bet they will anyway.

I think you need to offer this at the level of the shop. Sell schools RaspPis with the disable bit already set. If that means that us hackers never get their hands on an overvoltable board then too bad.

The alternative is to offer that image which sets the bit. In most cases the incoming RaspPis will go through some sort of IT department, even if it is just Mr Smith in his spare periods. But it should also be possible for Mr Smith to tell which boards have the disable bit set, and which boards have already been overvolted.

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Re: config.txt

Tue Feb 14, 2012 11:45 am

@PimpMyPi

See my post on the first page. I gave a link to a definition of all the CEA modes.

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Re: config.txt

Tue Feb 14, 2012 11:53 am

Sorry for the four-in-a-row.

If the special boot image finds that the board has been over-volted already, it should refuse to set the disable bit.

The damage is already done, so setting the disable bit will achieve very little.

And this will protect little Timmy's own RaspPi when he asks the school's IT department to fix it.

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Re: config.txt

Tue Feb 14, 2012 12:09 pm

rurwin said:


@PimpMyPi

See my post on the first page. I gave a link to a definition of all the CEA modes.



Thanks, that makes my life a bit easier!

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Re: config.txt

Tue Feb 14, 2012 12:59 pm

NAB said:


Nope. All you need to do is take the SD card out, put it in a Windows machine and create/edit the config.txt file.


Which is a rather big hurdle, unless there are Windows machines right next to the Raspberrys, that also do have sd card readers.


Then there would need to be a piece of paper sent out with every single RPi which says "Warning – to ensure your warranty is not voided, download this image (link), put it on an SD and boot the RPi with it in once." – if not, how would people know to flip the switch?



Sorry i was'nt clear enough, i meant the OTP bit that dom mentioned. As others have said, the Foundation could activate that on every Pi that is intended for schools. Or they could enable it on the included SD Card, so that the schools also have a choice to change the setting if they want to.

rurwins point about protecting little Timmy's Pi is also valid of course.

Another not entirely serious take on the situation:

Since Pi's are so cheap it would be an ideal tool to let children(that are old enough) learn that actions have consequences. So if they void the warranty they pay the replacement. That just might prevent that they grow up to be adults that put milk in printers.

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Re: config.txt

Tue Feb 14, 2012 1:13 pm

khulat said:

Which is a rather big hurdle, unless there are Windows machines right next to the Raspberrys, that also do have sd card readers.
And that may well not be the case for some. I do know that the school my son will be going to when he reaches 11 currently dishes out laptops to every pupil...

 so that the schools also have a choice to change the setting if they want to.
Indeed. Again, you misunderstand. For the school to make this choice, they need to be fully informed of the options and implications and also have a very simple way of acting on that choice.

Bear in mind that 'the school' may not be computer literate and you certainly can't assume that they trawl through this forum. The kids, on the other hand...

Another not entirely serious take on the situation:

Since Pi's are so cheap it would be an ideal tool to let children(that are old enough) learn that actions have consequences. So if they void the warranty they pay the replacement. That just might prevent that they grow up to be adults that put milk in printers.


That is a good point. If it were the pupils buying the RPis with their own cash, I'd be inclined to agree with you.

Nicholas.

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