Hi, On Fri, Nov 28, 2014 at 12:50:29PM +0100, Hans de Goede wrote: > Hi ChenYu, > > On 11/28/2014 10:20 AM, wens Tsai wrote: > >Hi Hans, > > > >Thanks for completing SPL support on the A31. > >I've managed to boot mainline U-boot on my Hummingbird A31. > > > >One issue I ran into is that with DCDC1 set at 3.0V, > >mmc0 is very unstable in the kernel. All operations > >timeout and the kernel panics because the rootfs isn't > >available. > > > >Raising the voltage to 3.3V gets rid of the problem, > >but I'm not sure that is the correct solution. > > The fex file for the mele boards says dcdc1 should be 3.3V not > 3.0V and that makes sense really, since 3.3V is a standard > voltage, while 3.0V is not. > > However the fex file for the Hummingbird says 3.0V and my > Mele M9 works fine with the current u-boot setting of 3.0V. > > I've just booted my M9 into the original firmware and that is > actually using 3.3V so changing things to 3.3V does seem to > be the right thing. > > Maxime, I seem to remember you telling me that the Colombus > is really using 3.0V. > > Maxime can you confirm this? Is that routed to the mmc power ?
I just checked on the schematics, and while the VCC line is called VCC-3V0, it's indeed said later in this document that it should be set to 3.3V... I'll cross-check that with a multimeter on the board along with your other tests. > > It could be that 3.0V is enough for the A31 itself, but that > on boards which do not have a separate power-supply for the > mmc 3.3V is used ? > > I'm fine with moving to 3.3V, I'm wondering if we should > make it configurable like the DLDO# and ALDO# voltages, > see drivers/power/Kconfig, with a 3.3V voltage and an > override in the Colombus defconfig ? I'm not sure what you're referring to here. All I see is battery drivers. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
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