On 10/26/18 6:37 PM, Lucas Stach wrote: > Am Freitag, den 26.10.2018, 15:03 +0300 schrieb Dmitry Osipenko: > [...] >>> On the other hand, the tegra20 cpufreq driver is common across a lot of boards. >>> What will happen if the DT for some of the boards isn't correct and missed the >>> necessary regulator node ? >> >> AFAIK, there is assumption that bootloader should setup regulators in >> a way that kernel could work properly at max clock rates. Otherwise >> things won't work. > > This isn't true. The assumption is that the bootloader sets up the > regulators such that stable operation at the CPU speed used by the > bootloader is guaranteed. > > Often the bootloader doesn't know about specific SKUs, so drives things > at a rate/voltage that is safe across all SKUs [1], in which case the > bootloader is totally unaware of the voltage needed to run the CPU at > highest possible clock frequency. > > Regards, > Lucas > > [1] http://git.denx.de/?p=u-boot.git;a=commit;h=2364e151e432b4ccf32dc9e6147121253d4ff86d > Oh, okay. Thank you for pointing at [1], though the assumption is true for T20. I agree that it's better not to rely on configuration left from bootloader in general.
