Building an image for Raspberry Pi

[Ian Lepore]

On Thu, 2014-04-03 at 02:30 -0400, Glen Barber wrote:
> On Thu, Apr 03, 2014 at 02:28:11AM -0400, Shawn Webb wrote:
> > On Apr 03, 2014 02:19 AM -0400, Glen Barber wrote:
[...]
> > > 
> > > Do you have a slower SD card you can try?  I've seen that happen
> > > sporadically with Class 10 SD cards, but have not yet seen it on lesser
> > > speed SD cards.  (I still boot-test faster SD cards, but haven't hit
> > > this issue in a while though.)
> > 
> > The one I'm currently using is a class 10 card, so maybe that's it. I've
> > got a class 2 microsd card with an adapter that I'll try. I'll report
> > back soon-ish with results.
> 
> Ok, thanks for experimenting.  I thought there was a fix committed for
> this, but maybe I'm wrong.
> 
> Glen

No, we've never figured out the RPi sdcard mystery.  We've tried forcing
the driver to run the card bus faster and slower and while it sometimes
seems to change things, it's never really been a fix.  I've gone as far
as putting an oscilliscope on the clock and data lines and everything
looks normal up to the point where the bus locks up, then it "just stops
working".  There must be some subtle timing thing with our driver that
gets the hardware into a bad state, and the u-boot and linux drivers are
just enough different that they don't encounter it.

-- Ian