portets
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Could this be related to the Pi's USB issues?

Thu Aug 22, 2013 11:12 pm

https://plus.google.com/u/0/11696035749 ... Zpndv4BCCD

I don't know enough about this to know if it's related.

Angelus88
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Re: Could this be related to the Pi's USB issues?

Thu Aug 22, 2013 11:32 pm

.
Last edited by Angelus88 on Wed Aug 28, 2013 10:11 pm, edited 1 time in total.

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mahjongg
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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 12:01 am

it might be one issue, I doubt it will be the end of all Raspberry PI USB issues. It does make mincemeat of the idea that USB is a system that should work perfectly on all systems with all devices, under all circumstances. Its USB not a miracle. Its more a miracle that it works as well is it often does, seen as to how complex the inner workings of USB are.

gritz
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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 12:27 am

mahjongg wrote:it might be one issue, I doubt it will be the end of all Raspberry PI USB issues. It does make mincemeat of the idea that USB is a system that should work perfectly on all systems with all devices, under all circumstances. Its USB not a miracle. Its more a miracle that it works as well is it often does, seen as to how complex the inner workings of USB are.
This! Considering the backward compatibility that has to be built on top of a technology originally designed by a committee that couldn't have had the faintest idea where it would all lead it is indeed a miracle that it works at all, especially as so many hosts / devices take the odd liberty with various aspects of the spec. In Win / x86 land the instruction to uncheck the system setting box marked "turn off this [USB] device to save power" is often pretty close to the top of the list in install / troubleshooting instructions for e.g. USB audio interfaces.

Someone like gsh might be better able to comment in a Linux / Pi specific way (apologies to gsh in advance if he gets a deluge of pm's!)

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pluggy
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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 4:51 am

Related possibly. I reckon from wading through much bumph that the main problems stem from forcing the BCM2835 into being a USB host when it was designed only to be a client and writing the driver from dubious documentation with dubious parentage. (paraphrase ;) )
Don't judge Linux by the Pi.......
I must not tread on too many sacred cows......

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mahjongg
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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 11:51 am

USB OTG systems are host systems! Only thing is they can drop the hosting role and act as normal USB devices when attached to another host. see http://en.wikipedia.org/wiki/USB_On-The-Go

So the talk that "the main problems stem from forcing the BCM2835 into being a USB host when it was designed only to be a client" are baseless, the hardware was designed to be an USB host (and more). It is just that the hub chip used in the model B blocked the use as USB device, otherwise the PI could have been a full OTG device.

Instead its just that the architecture of the BCM2835's USB hardware is quite basic, and some tasks that in other implementations is done in hardware is done in software on the PI.

The core of that USB software was bought as IP from a third party, and that makes it harder to go look for and fix issues when they are there. And with USB there will always be issues with some devices, as many USB devices tend to deviate from the rules, and therefore need tweaks.

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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 7:41 pm

mahjongg wrote:And with USB there will always be issues with some devices, as many USB devices tend to deviate from the rules, and therefore need tweaks.
Best "tweaks" would be (in order) returning the device to the vendor as "unsuitable for intended purpose (does not work correctly)" or taking it to your local electronics recycling center. After that, spreading the word not to buy that item.

gritz
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Re: Could this be related to the Pi's USB issues?

Fri Aug 23, 2013 7:56 pm

W. H. Heydt wrote:
mahjongg wrote:And with USB there will always be issues with some devices, as many USB devices tend to deviate from the rules, and therefore need tweaks.
Best "tweaks" would be (in order) returning the device to the vendor as "unsuitable for intended purpose (does not work correctly)" or taking it to your local electronics recycling center. After that, spreading the word not to buy that item.
Careful now! ;)

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