On Fri, Jan 05, 2018 at 03:35:13PM +0100, Geert Uytterhoeven wrote: > Hi Simon, > > On Fri, Jan 5, 2018 at 3:04 PM, Simon Horman <horms@xxxxxxxxxxxx> wrote: > > On Wed, Jan 03, 2018 at 01:47:08PM +0100, Geert Uytterhoeven wrote: > >> On Wed, Jan 3, 2018 at 1:18 PM, Simon Horman <horms+renesas@xxxxxxxxxxxx> wrote: > >> > From: Takeshi Kihara <takeshi.kihara.df@xxxxxxxxxxx> > >> > > >> > This patch adds Z2 clock divider support for R-Car Gen3 SoC. > >> > > >> > Signed-off-by: Takeshi Kihara <takeshi.kihara.df@xxxxxxxxxxx> > >> > Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx> > > >> As the CPG/MSSR driver now has suspend/resume support, do we need > >> a notifier to restore the Z or Z2 registers? Or is that handled automatically > >> by cpufreq during system resume, for both the primary and the secondary > >> CPU cores? > > > > I am a bit unsure. > > > > When using the A57 cores, which is the default case, the Z clk is queried > > by CPUFreq on resume. It appears that on my system its already set to the > > correct value but I assume if it was not then it would be reset. However, > > this does not cover Z2 clk. So perhaps to be safe we need to register > > notifiers and make sure they they play nicely with CPUFreq? > > Of course the CPU is special: unlike many other devices, it must be running > when the kernel is reentered upon system resume. > It may be running using a different frequency setting, though. > However, following "opp-suspend", the system will always suspend with the > Z clock running at 1.5GHz, which is the default? > So Z is probably OK. > > It's more interesting to check what happens when the little cores are > enabled as well (unfortunately that requires different firmware). > 1. Does cpufreq handle them correctly when they are onlined again during > system resume? > 2. What happens if you offline all big cores, and enter system suspend > running with little cores only? > Perhaps that's prevented by the "opp-suspend" property as well? Thanks for clarifying the problem. I should be able to install updated firmware on: i* r8a7796 (M3-W) ES1.0 / Salvator-X; and * r8a7795 (H3) ES2.0 / Salvator-XS. * But not easily r8a7795 (H3) / Salvator-X Do you know what the minimal / desired firmware version is to exercise the scenarios you describe.
