Re: [RFC v3 00/10] DDR/L3 Scaling support on SDM845 and SC7180 SoCs

From: Sibi Sankar <sibis@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>,
	sboyd@kernel.org, georgi.djakov@linaro.org, saravanak@google.com,
	nm@ti.com, bjorn.andersson@linaro.org, agross@kernel.org,
	david.brown@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com,
	rjw@rjwysocki.net, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org, dianders@chromium.org,
	mka@chromium.org, vincent.guittot@linaro.org,
	amit.kucheria@linaro.org, ulf.hansson@linaro.org,
	linux-kernel-owner@vger.kernel.org
Subject: Re: [RFC v3 00/10] DDR/L3 Scaling support on SDM845 and SC7180 SoCs
Date: Thu, 19 Mar 2020 16:27:13 +0530	[thread overview]
Message-ID: <e2cab5f55b9d26849e45d3df951ad7b9@codeaurora.org> (raw)
In-Reply-To: <20200319102411.oivesngrk7gy7vtw@vireshk-i7>

On 2020-03-19 15:54, Viresh Kumar wrote:
> On 19-03-20, 15:41, Sibi Sankar wrote:
>> Viresh,
>> Saravana's example does show a device
>> with multiple opp tables but doesn't
>> need multiple opp table support to
>> land though (since it works fine with
>> the current implementation). I am more
>> interested  in understanding your/
>> Stephen's/Saravana's stance on adding
>> multiple opp-table support. Personally
>> I feel its inevitable, since multiple
>> qc drivers using interconnect opp-tables,
>> routinely need vote on multiple paths in
>> a non-trivial manner.
> 
> The OPP core doesn't support multiple OPP tables for a device and I
> don't understand how it will. And so I have been waiting for a reply.

This series tries to add minimal support
for multiple opp-tables per device and
can be tested on db845c/sdm845mtp/sc7180.
Debugfs still needs to be fixed though and
fixing it did feel non-trivial (I can get
to it if we reach a consensus). Perhaps we
can fork out icc oppp-tables from regular
opp-tables and allow only multiple instances
of icc opp-tables per device(though Rob
didn't like the bindings associated with it)
that way all the current users wont be
affected but from what I've tested the
series shouldn't cause any regression.

> 
>> >
>> > Could you please post a link to the discussion that you are referring to
>> > here?
>> > I looked at a few links posted in the cover letter as dependencies and
>> > it seems
>> > like the discussions are pending for *months* and not weeks but I
>> > might have looked
>> > at the wrong ones.
>> 
>> https://lore.kernel.org/lkml/20200114103448.odnvqawnqb3twst5@vireshk-i7/
>> 
>> Rajendra,
>> Viresh is referring to ^^ one
> 
> Right, thanks.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.