Re: [PATCH v2 0/3] Power10 basic energy management

Excerpts from Gautham R Shenoy's message of July 13, 2020 8:48 pm:

On Mon, Jul 13, 2020 at 03:23:21PM +1000, Nicholas Piggin wrote:

quoted

Excerpts from Pratik Rajesh Sampat's message of July 10, 2020 3:22 pm:

quoted

Changelog v1 --> v2:
1. Save-restore DAWR and DAWRX unconditionally as they are lost in
shallow idle states too
2. Rename pnv_first_spr_loss_level to pnv_first_fullstate_loss_level to
correct naming terminology

Pratik Rajesh Sampat (3):
  powerpc/powernv/idle: Exclude mfspr on HID1,4,5 on P9 and above
  powerpc/powernv/idle: save-restore DAWR0,DAWRX0 for P10
  powerpc/powernv/idle: Rename pnv_first_spr_loss_level variable

 arch/powerpc/platforms/powernv/idle.c | 34 +++++++++++++++++----------
 1 file changed, 22 insertions(+), 12 deletions(-)

These look okay to me, but the CPU_FTR_ARCH_300 test for 
pnv_power9_idle_init() is actually wrong, it should be a PVR test 
because idle is not completely architected (not even shallow stop 
states, unfortunately).

It doesn't look like we support POWER10 idle correctly yet, and on older
kernels it wouldn't work even if we fixed newer, so ideally the PVR 
check would be backported as a fix in the front of the series.

Sadly, we have no OPAL idle driver yet. Hopefully we will before the
next processor shows up :P

Abhishek posted a version recently :
https://patchwork.ozlabs.org/project/skiboot/patch/20200706043533.76539-1-huntbag@linux.vnet.ibm.com/

Yep, I saw that. Still keen to get it working, just had other priorities 
in the short term. We'll need to do this OPAL v4 thing for it.

Thanks,
Nick