linux-kernel - Re: [PATCH v2 4/6] clk: qcom: Use HW_CTRL_TRIGGER flag to switch video GDSC to HW mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8257f7b3-dfb8-4683-85de-600f3b1ed54b@linaro.org>
Date:   Sat, 2 Sep 2023 14:03:38 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Jagadeesh Kona <quic_jkona@...cinc.com>,
        Abel Vesa <abel.vesa@...aro.org>
Cc:     "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>,
        Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Taniya Das <tdas@....qualcomm.com>, linux-pm@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm@...r.kernel.org,
        Ajit Pandey <quic_ajipan@...cinc.com>,
        Imran Shaik <quic_imrashai@...cinc.com>
Subject: Re: [PATCH v2 4/6] clk: qcom: Use HW_CTRL_TRIGGER flag to switch
 video GDSC to HW mode

On 28.08.2023 08:48, Jagadeesh Kona wrote:
> 
> 
> On 8/26/2023 4:17 PM, Konrad Dybcio wrote:
>> On 23.08.2023 12:41, Abel Vesa wrote:
>>> On 23-08-16 19:56:46, Konrad Dybcio wrote:
>>>> On 16.08.2023 16:57, Abel Vesa wrote:
>>>>> From: Jagadeesh Kona <quic_jkona@...cinc.com>
>>>>>
>>>>> The current HW_CTRL flag switches the video GDSC to HW control mode as
>>>>> part of GDSC enable itself, instead of that use HW_CTRL_TRIGGER flag to
>>>>> give consumer drivers more control and switch the GDSC mode as and when
>>>>> required.
>>>>>
>>>>> HW_CTRL_TRIGGER flag allows consumer drivers to switch the video GDSC to
>>>>> HW/SW control modes at runtime using dev_pm_genpd_set_hwmode API.
>>>>>
>>>>> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
>>>>> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
>>>>> ---
>>>> Do we have any use for the HW_CTRL flag?
>>>>
>>>> Perhaps it should be renamed to HW_CTRL_ALWAYS?
>>>>
>>>> Or even better, *if and only if* that is necessary, add a common
>>>> property like "always_hw_managed" to the genpd code?
>>>
>>> The HW_CTRL flag is still needed for the consumers that expect the GDSC
>>> to be have the HW control bit set right after it gets enabled.
>> Guess the correct question here would be.. Are there any?
>>
> 
> Yes, Display GDSC(mdss_gdsc) is required to be controlled always in HW control mode when it is enabled.
Oh really?

Looking at msm-5.10 techpack, only the SDE RSC driver seems to
trigger regulator fast mode (so, enabling gdsc hw_ctrl on downstream).

Konrad