On Wed, Aug 31, 2022 at 03:17:26PM -0700, Dixit, Ashutosh wrote:
On Wed, 31 Aug 2022 14:45:38 -0700, Rodrigo Vivi wrote:
Hi Rodrigo,
We need to inform PCODE of a desired ring frequencies so PCODE update the memory frequencies to us. rps->min_freq and rps->max_freq are the frequencies used in that request. However they were unset when SLPC was enabled and PCODE never updated the memory freq.
v2 (as Suggested by Ashutosh): if SLPC is in use, let's pick the right frequencies from the get_ia_constants instead of the fake init of rps' min and max.
v3: don't forget the max <= min return
v4: Move all the freq conversion to intel_rps.c. And the max <= min check to where it belongs.
v5: (Ashutosh) Fix old comment s/50 HZ/50 MHz and add a doc explaining the "raw format"
I think we both agree that mostly the way this patch is written it is to add SLPC but not risk disturbing host turbo, specially old platforms (CHV/VLV/ILK and pre-Gen 6). Also these freq units (sometimes 16.67 MHz units, sometimes 50 MHz, sometime MHz) in different places in the driver and different product generations is hugely confusing to say the least. For old platform we don't really know what units the freq's are in, we only know intel_gpu_freq will magically convert freq's to MHz. In any case let's work with what we have.
yeap!
@@ -130,6 +123,12 @@ static void gen6_update_ring_freq(struct intel_llc *llc) if (!get_ia_constants(llc, &consts)) return;
- /*
* Although this is unlikely on any platform during initialization,* let's ensure we don't get accidentally into infinite loop*/- if (consts.max_gpu_freq <= consts.min_gpu_freq)
return;As I said I would remove reference to "infinite loop", I am not seeing any infinite loop, maybe just delete the comment.
Also as I said I see the check above should be completely removed (so it is actually a pre-existing bug in the code). However since you want to carry it forward in order not to risk disturbing legacy behavior that's fine.
I know we can get the infinit loop because I faced it here on a bad config where min = max. os if min >= max, the for loop will never close. And in case we have some fused parts with min = max we will take a while to figure out what's going on during po. and who knows about older platforms and skus out there as well.
I will keep the comment so we don't end up removing it from here.
Rest LGTM:
Reviewed-by: Ashutosh Dixit ashutosh.dixit@intel.com
Thanks