linux-kernel - Re: [PATCH V5 RESEND 5/5] venus: pm_helpers: Use dev_pm_genpd_set

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Message-ID: <5c78ad52-524b-4ad7-b149-0e7252abc2ee@linaro.org>
Date: Sun, 14 Apr 2024 13:39:59 +0100
From: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To: Jagadeesh Kona <quic_jkona@...cinc.com>,
 Bjorn Andersson <andersson@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Stanimir Varbanov <stanimir.k.varbanov@...il.com>,
 Vikash Garodia <quic_vgarodia@...cinc.com>,
 Mauro Carvalho Chehab <mchehab@...nel.org>,
 Ulf Hansson <ulf.hansson@...aro.org>, "Rafael J . Wysocki"
 <rafael@...nel.org>, Kevin Hilman <khilman@...nel.org>,
 Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Konrad Dybcio <konrad.dybcio@...aro.org>, Andy Gross <agross@...nel.org>,
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Abel Vesa <abel.vesa@...aro.org>
Cc: linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
 linux-pm@...r.kernel.org, Taniya Das <quic_tdas@...cinc.com>,
 Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
 Imran Shaik <quic_imrashai@...cinc.com>,
 Ajit Pandey <quic_ajipan@...cinc.com>
Subject: Re: [PATCH V5 RESEND 5/5] venus: pm_helpers: Use
 dev_pm_genpd_set_hwmode to switch GDSC mode on V6

On 13/04/2024 16:20, Jagadeesh Kona wrote:
> The Venus driver requires vcodec GDSC to be ON in SW mode for clock
> operations and move it back to HW mode to gain power benefits. Earlier,
> as there is no interface to switch the GDSC mode from GenPD framework,
> the GDSC is moved to HW control mode as part of GDSC enable callback and
> venus driver is writing to its POWER_CONTROL register to keep the GDSC ON
> from SW whereever required. But the POWER_CONTROL register addresses
> are not constant and can vary across the variants.
> 
> Also as per the HW recommendation, the GDSC mode switching needs to be
> controlled from respective GDSC register and this is a uniform approach
> across all the targets. Hence use dev_pm_genpd_set_hwmode() API which
> controls GDSC mode switching using its respective GDSC register.
> 
> In venus V6 variants, the vcodec gdsc gets enabled in SW mode by default
> with new HW_CTRL_TRIGGER flag and there is no need to switch it to SW
> mode again after enable, hence add check to avoid switching gdsc to SW mode
> again after gdsc enable. Similarly add check to avoid switching GDSC to HW
> mode before disabling the GDSC, so GDSC gets enabled in SW mode in the next
> enable.
> 
> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> ---

When I tested this out on sm8250 a few months ago it was broken.

I don't quite see in your commit logs, how the breakage was addressed.

Can you provide some details ?

---
bod