linux-kernel - Re: [PATCH 1/3] dt-bindings: interconnect: add clocks property to enable QoS on sa8775p

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: <3c4751c3-52d5-408e-ae80-df22bcff5d8a@oss.qualcomm.com>
Date: Wed, 3 Sep 2025 14:42:01 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Georgi Djakov <djakov@...nel.org>, Krzysztof Kozlowski <krzk@...nel.org>,
        Odelu Kukatla <odelu.kukatla@....qualcomm.com>,
        Rob Herring
 <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>
Cc: Raviteja Laggyshetty <quic_rlaggysh@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mike Tipton <mike.tipton@....qualcomm.com>
Subject: Re: [PATCH 1/3] dt-bindings: interconnect: add clocks property to
 enable QoS on sa8775p

On 8/28/25 11:59 PM, Georgi Djakov wrote:
> On 8/28/25 9:20 PM, Krzysztof Kozlowski wrote:
>> On 28/08/2025 20:16, Odelu Kukatla wrote:
>>>
>>>>> QoS configuration is essential for managing latency and bandwidth across
>>>>> subsystems such as CPU, GPU, and multimedia engines. Without it, the
>>>>> system may experience performance degradation, especially under
>>>>
>>>> So how was it working for the last 2 years?
>>>>
>>> The system may function normally without this feature. However, enabling
>>
>>
>> Huh? So you agree but keep continuing the discussion?
>>
>> I don't understand what we are discussing in such case, but just to
>> close the topic from my side and be explicit: based on above you cannot
>> break the ABI.
> 
> To be even more specific, if we already have some DT binding without any
> clocks and reg properties, we can't just suddenly change them from now
> on to be "required". But they can still be "optional" and this will not
> break the ABI, right? The old DT is still valid and the QoS will be
> active when the new properties are present and this is handled properly
> by the driver.

Correct and this very approach was used to retrofit QoS onto an even older
sc7280 icc driver.

The icc-rpmh core already ignores QoS configuration if the clocks are not
provided.

Konrad