08.05.2020 13:31, Thierry Reding пишет: ... >> Is it legal to touch DPAUX registers while DPAUX is in a suspended state? > > DPAUX is never runtime suspended and the dependency from the I2C > controller on DPAUX should ensure that they are suspended and resumed in > the right order during system sleep. 1. Could you please explain why DPAUX is never suspended? Isn't it a problem? It looks a bit odd that driver is doing this [1][2]. RPM is supposed to be used for the *dynamic* power management. Should we remove RPM usage from the DPAUX driver? [1] https://elixir.bootlin.com/linux/v5.7-rc4/source/drivers/gpu/drm/tegra/dpaux.c#L524 [2] https://elixir.bootlin.com/linux/v5.7-rc4/source/drivers/gpu/drm/tegra/dpaux.c#L591 2. Could you please explain why I2C driver has to care about restoring the pinmux state? Why pinctrl driver isn't doing that for I2C and everything else?