On 04/25/2017 07:23 PM, Leonard Crestez wrote: > 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.
Hehehe :-) > 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). Oh that's nice , thanks ! I don't have SDB and I hacked it up after a brief discussion with Fabio without even compile-testing it, thus RFC. Glad to hear it works and thanks for testing it ! Can you add a formal Tested-by please ? -- Best regards, Marek Vasut