On Tue, 2017-04-25 at 14:02 -0300, Fabio Estevam wrote: > On Tue, Apr 25, 2017 at 2:02 PM, Fabio Estevam <feste...@gmail.com> wrote: > > > > Hi Leonard, > > > > On Tue, Apr 25, 2017 at 1:57 PM, Leonard Crestez > > <leonard.cres...@nxp.com> wrote: > > > > > > The board file for imx6sx-dbg overrides cpufreq operating points to use > > > higher voltages. This is done because the board has a shared rail for > > > VDD_ARM_IN and VDD_SOC_IN and when using LDO bypass the shared voltage > > > needs to be a value suitable for both ARM and SOC. > > > > > > This was introduced in: > > > > > > commit 54183bd7f766 ("ARM: imx6sx-sdb: add revb board and make it > > > default") > > > > > > This only only applies to LDO bypass mode, a feature not present in > > > upstream. When LDOs are enabled the effect is to use higher voltages than > > > necesarry for no good reason. > > > > > > Setting these higher voltages can make some boards fail to boot with ugly > > > semi-random crashes, reminiscent of memory corruption. These failures > > > happen the first time the lowest idle state is used. Remove the OPP > > > override in order to fix those crashes. > > > > > > Signed-off-by: Leonard Crestez <leonard.cres...@nxp.com> > > > > > > --- > > > It's not clear exactly why the crashes happen. Perhaps waking up from idle > > > draws more power than is available? Removing this override is a correct > > > change anyway so maybe there is no need to investigate deeper.
> > Marek just sent a similar one a few minutes ago: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/503230.html > Forgot to add Marek. Wow, that was literally 15 minutes before my patch. In my defense I did search the archives before starting to format the patch but it had not arrived yet. Anyway, that version also sets the supply for reg_arm and reg_soc. It is not necessary for fixing the crash I'm seeing but is good because it will result in the minimum voltage on VDD_ARM_SOC_IN rather than a fix 1375mv. I tested Marek's patch and it works fine on my rev B board (which otherwise fails to boot upstream). -- Regards, Leonard