linux-kernel - Re: [PATCH RESEND v3 5/5] venus: pm_helpers: Use dev_pm_genpd_set

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Date:   Sat, 4 Nov 2023 13:00:53 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Abel Vesa <abel.vesa@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...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>
Cc:     Taniya Das <tdas@....qualcomm.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-media@...r.kernel.org,
        Jagadeesh Kona <quic_jkona@...cinc.com>
Subject: Re: [PATCH RESEND v3 5/5] venus: pm_helpers: Use
 dev_pm_genpd_set_hwmode to switch GDSC mode



On 11/3/23 11:44, Bryan O'Donoghue wrote:
> On 01/11/2023 09:04, Abel Vesa wrote:
>> From: Jagadeesh Kona <quic_jkona@...cinc.com>
>>
>> This change demonstrates the use of dev_pm_genpd_set_hwmode API from
>> video driver to switch the video mvs0 gdsc to SW/HW modes at runtime
>> based on requirement.
>>
>> This change adds a new boolean array member vcodec_pmdomains_hwctrl in
>> venus_resources structure to indicate if GDSC's have HW control support
>> or not. This data is used in vcodec_control_v4() to check if GDSC has
>> support to switch to HW control mode and then call dev_pm_genpd_set_hwmode
>> to switch the GDSC mode.
>>
>> Before the GDSC HWCTL was available to the consumer, the venus driver
>> needed to somehow keep the power from collapsing while under the driver
>> control. The only way to do that was to clear the CORE_PWR_DISABLE bit
>> (in wrapper POWER_CONTROL register) and, respectively, set it back after
>> the driver control was completed.
>>
>> Now, that there is a way to switch the GDSC HW/SW control back and
>> forth, the CORE_PWR_DISABLE toggling can be dropped.
>>
>> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
>> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> 
> So I plan to give this a test on rb5 and db410c
> 
> My q here though is - has anybody on the submission list tested this through suspend/resume and vdd min ?
I think that only chromebooks (sc7[12]80) and sc7180-acer-aspire1.dts
are able to hit vddmin upstream as of today

Konrad