Hi, On 05/11/2014 10:43 PM, Hans de Goede wrote: > Hi, > > On 05/11/2014 11:53 AM, Siarhei Siamashka wrote: >> It has been confirmed that a substantial percentage of cubieboard2 >> and cubietruck users are having stability issues. These issues are >> caused by having various voltages optimistically configured way too >> low. Because each unit has its own tolerances, not everyone can >> easily reproduce these problems. >> >> To address the issue, we take the updated settings from: >> >> https://github.com/cubieboard/cubie_configs/tree/09e511721697/sysconfig/linux >> This repository is relevant because it is referenced from: >> >> http://docs.cubieboard.org/tutorials/ct1/development/compiling_latest_kernel_for_cubietruck_cubieboard3 >> Please note that there is also a sunxi-boards repository fork at >> https://github.com/cubieboard (with bad settings) and this makes >> things more confusing than necessary. >> >> Signed-off-by: Siarhei Siamashka <[email protected]> >> --- >> sys_config/a20/cubieboard2.fex | 18 +++++++++--------- >> sys_config/a20/cubietruck.fex | 16 ++++++++-------- >> 2 files changed, 17 insertions(+), 17 deletions(-) >> >> diff --git a/sys_config/a20/cubieboard2.fex b/sys_config/a20/cubieboard2.fex >> index 1436df8..c8c9c74 100644 >> --- a/sys_config/a20/cubieboard2.fex >> +++ b/sys_config/a20/cubieboard2.fex >> @@ -1,14 +1,14 @@ >> [product] >> version = "100" >> -machine = "cubieboard" >> +machine = "cubieboard2" >> >> [platform] >> eraseflag = 0 >> >> [target] >> boot_clock = 912 >> -dcdc2_vol = 1400 >> -dcdc3_vol = 1250 >> +dcdc2_vol = 1450 > > This makes no sense, since in the dvfs table there is: > max_freq = 912000000 > > LV2_freq = 912000000 > LV2_volt = 1425 > > S0 1.425 volt would make a lot more sense. Also Page 31 > of A20+Datasheet+v1.0+20130227.pdf says that the MAX > CPU and systemvoltage is 1425 volts. So what this patch > effectively does is overvolt the CPU cores and base system. > > Now overvolting is a well know trick when doing overclocking, > the question is do we really want to ship a config which > overvolts by default? > > My first instinctive reaction is no we don't. But if this > cures our stability issues, then I think it makes sense to > do so, in this case u-boot should be changed to init the > cpu voltage to 1.425 volt by default too.
Follow up question, have you tried overvolting your A10 Lime to 1.425 volt to see if that fixes the L2 cache issues you've been seeing there. I know you said 1.450 volt fixes it, but I wonder if 1.425 volt fixes it too, because in that case is may make sense to simply make 1.425V the default voltage (max speed) everywhere. Likewise it would be interesting to repeat the L2 cache failures on (very) low clock speeds on the A20 with the new DVFS table. Regards, Hans -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
