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USB update from Gordon, new direction

e14 Contributor

"Unfortunately I've been unable to create a more credible improvement for the USB issues we currently have. Improvements to latency actually have a detrimetal effect to some types of transport (split transactions) which isn't going to be fixed any time soon.

 

So instead I've been spending a little time horsing around with the EHCI interface to see if I can create a software implementation of the EHCI host interface for the DWC_OTG hardware, this would solve our problems because then we can push this code onto the VPU which has a very low interrupt latency and interrupt overhead.

 

But unfortunately it is going to take time and I could probably do with some volunteers to help do the EHCI interface. I'm hoping to get a simple one in place first (that works with most simple transactions) then people can begin helping in the spirit of open software!"

 

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=28&t=12097&start=556

Parents

  • USB will work when they find the formula to create milk out of a rock. I believe I mentioned it long time ago, but the piece of IP that Broacdom got from Synopsys for the BCM2835 is an implementation of USB OTG, it will be very challenging to pretend make it work as a full featured USB HOST.

     

    Can you do some workaround to get some limited functionality working properly for some devices, probably yes, but it will never reach Eben's promise that you can do with the Pi what you can do with any other computer, that has been a misleading statement since day way as it is the permanent tag message on the Blog header.

     

    Still the Rpi is a cool gadget to thinker with Linux.

     

    -J

  • in reply to jamodio

    jamodio wrote:

     

    ...Still the Rpi is a cool gadget to thinker with Linux.

     

    -J

     

    I would venture to say that ~most~ people don't have a computer in order just to "tinker" with it's operating system - although some of us will doubtless have spent far too much time poking about in the innards because something doesn't work, or just out of curiosity... image

     

    Nope, for most a computer is a box for doing stuff - interfacing with a sensor, browsing, coding, playing media, writing that novel and all the other wonderful / mundane things. "Tinkering is fine, so long as it's not compulsory!" It shouldn't be compulsory either - not everyone wants to be a dentist, or a lion tamer - even though they are doubtless noble professions.

     

    Ironically, for those folks that are keen on destruction testing an operating system then the best choice of hardware IMO is something absolutely bulletproof. Then, when the rainbow / blue screen / spinning beachball of abject misery appears one know's it's directly related to one's own input and not some random hardware / driver burp that one has no control over. That's why that with hindsight the original choice of Fedora for the Pi seems a bit ...umm... foolhardy. Beta hardware + alpha software = debugging purgatory.

  • in reply to e14 Contributor

    Noticed that I said "gadget" not "computer" ...

     

    Jonathan Garrish wrote:

    Beta hardware + alpha software = debugging purgatory.

     

    Amen

  • in reply to jamodio

    jamodio wrote:

     

    Noticed that I said "gadget" not "computer" ...

     

     

    Noted and understood!

  • in reply to e14 Contributor

    Actually it's worse than that, more like:

     

    Beta hardware + alpha software + closed source + restricted doc = not a chance

  • in reply to morgaine

    Beta hardware + alpha software + closed source + restricted doc + management focused on marketing

  • in reply to e14 Contributor

    The management isn't focussed on marketing. It's a charity foundation focussed on the education of computer science.... image

    As long as it's just me wondering what the money is used for and not the British tax system it's fine I guess.

    The part I really loved yesterday was when the fanboys started to say that the Pi was no longer in Beta stage, as it was already rev. 1.3 hardware.

    It's however considered being a development board, so it's normal there are some minor issus. Am I glad there only are minor issues...

     

    It's all in the hands of Gordon now. I guess we already know who will catch the blame if things don't work out as promised.

    For a charity foundation, they really play that game like a non charity company.

     

    Maybe at that moment we will have (hopefully better) working alternatives and sales will start to dry up. People will rest upon the Pi usb issues.

    It wouldn't suprise me due to that, they will say their educational goal failed. But they still have a few tricks in their big hat to boost up sales, like the camera module and the release of android for the 512MB version, so there is no need to worry for the near future.

  • in reply to e14 Contributor

    It wouldn't suprise me due to that, they will say their educational goal failed.

    Just IMHO, the educational goal has long gone.

Reply Children
  • in reply to e14 Contributor

    selsinork wrote:

    Luc Cool wrote:

     

    Maybe at that moment we will have (hopefully better) working alternatives and [RasPi] sales will start to dry up...  It wouldn't suprise me due to that, they will say their educational goal failed.

    Just IMHO, the educational goal has long gone.

    At the US Hackspace tour last month in San Francisco, Rob Bishop said the educational release is stll (IIRC) another year off and it's up to the community to create the software to make it happen.  So IMO saying the educational goal has failed is premature.

     

    OTOH, a year from now the cheap hardware picture could be very different.  While it's unlikely anyone is going to be able to beat RasPi's US$25-35 retail for a bare board, the cost of systems that meet RasPi's educational platform goal are dropping quickly.  For example, the new US$249 Samsung Chromebook has a dual Cortex-A15 processor (first in the wild, I believe), 2GB of DRAM, 11.6" 1366 x 768 display, and 16GB SSD.  Its default is to boot as a Chromium browser, but there is a "developer mode".  So RasPi may end up as a catalyst for cheap computers suitable for learning to program.  But this works towards RasPi's educational goal -- they have said many times that they welcome competition.

  • in reply to johnbeetem

    The educational goal justifies the foundation being a charity with a higher goal than selling Pi's...

    We shouldn't stare on the Pi pricetag. It's like buying a pc mobo. It's not a functional system on it's own.

    We already calculated the price for a classroom setup full of Pi's.

    You will have trouble finding second hand screens with a dvi or hdmi connection. Finding some with

    a composite input will be hard as well.

    If you have classroom full of pc's, you can learn to program and learn how to use word on the same machines.

    Not everyone wants to become a programming specialist...

    When I look at scratch, it reminds me of something we had several years ago.

    I think it was called logo and also had a creature walking on the screen... Not sure what happened to that one?

    I already see classes here that force the students to have an ipad. Wouldn't suprise me the teachers get one for free.

    How on heaven can you explain otherwise they wouldn't use a more open and cheaper android tablet?

    Most schools already have a classroom full off computers. It's up to the teachers what they do with it, and up to the gouvernment

    to define what they are suposed to learn with it. There is not much you can fubar on a pc with software, and alternatives like virtual machines can even help more in that. A good rescue plan like a proper configured image can also help a lot. Biggest problem is removing the chewing gum from the drive slots. Looks like the Pi isn't such a bad idea after all. (no drive slots)