On Wed, Jan 08, 2025 at 09:38:19PM +0530, Manaf Meethalavalappu Pallikunhi wrote: > > Hi Dmitry, > > > On 1/8/2025 6:16 PM, Dmitry Baryshkov wrote: > > On Wed, Jan 08, 2025 at 05:57:06PM +0530, Manaf Meethalavalappu Pallikunhi wrote: > > > Hi Dmitry, > > > > > > > > > On 1/3/2025 11:21 AM, Dmitry Baryshkov wrote: > > > > On Tue, Dec 31, 2024 at 05:31:41PM +0530, Manaf Meethalavalappu Pallikunhi wrote: > > > > > Hi Dmitry, > > > > > > > > > > On 12/30/2024 9:10 PM, Dmitry Baryshkov wrote: > > > > > > On Sun, Dec 29, 2024 at 08:53:32PM +0530, Wasim Nazir wrote: > > > > > > > From: Manaf Meethalavalappu Pallikunhi <quic_manafm@xxxxxxxxxxx> > > > > > > > > > > > > > > In QCS9100 SoC, the safety subsystem monitors all thermal sensors and > > > > > > > does corrective action for each subsystem based on sensor violation > > > > > > > to comply safety standards. But as QCS9075 is non-safe SoC it > > > > > > > requires conventional thermal mitigation to control thermal for > > > > > > > different subsystems. > > > > > > > > > > > > > > The cpu frequency throttling for different cpu tsens is enabled in > > > > > > > hardware as first defense for cpu thermal control. But QCS9075 SoC > > > > > > > has higher ambient specification. During high ambient condition, even > > > > > > > lowest frequency with multi cores can slowly build heat over the time > > > > > > > and it can lead to thermal run-away situations. This patch restrict > > > > > > > cpu cores during this scenario helps further thermal control and > > > > > > > avoids thermal critical violation. > > > > > > > > > > > > > > Add cpu idle injection cooling bindings for cpu tsens thermal zones > > > > > > > as a mitigation for cpu subsystem prior to thermal shutdown. > > > > > > > > > > > > > > Add cpu frequency cooling devices that will be used by userspace > > > > > > > thermal governor to mitigate skin thermal management. > > > > > > Does anything prevent us from having this config as a part of the basic > > > > > > sa8775p.dtsi setup? If HW is present in the base version but it is not > > > > > > accessible for whatever reason, please move it the base device config > > > > > > and use status "disabled" or "reserved" to the respective board files. > > > > > Sure, I will move idle injection node for each cpu to sa8775p.dtsi and keep > > > > > it disabled state. #cooling cells property for CPU, still wanted to keep it > > > > > in board files as we don't want to enable any cooling device in base DT. > > > > "we don't want" is not a proper justification. So, no. > > > As noted in the commit, thermal cooling mitigation is only necessary for > > > non-safe SoCs. Adding this cooling cell property to the CPU node in the base > > > DT (sa8775p.dtsi), which is shared by both safe and non-safe SoCs, would > > > violate the requirements for safe SoCs. Therefore, we will include it only > > > in non-safe SoC boards. > > "is only necessary" is fine. It means that it is an optional part which > > is going to be unused / ignored / duplicate functionality on the "safe" > > SoCs. What kind of requirement is going to be violated in this way? > > From the perspective of a safe SoC, any software mitigation that compromises > the safety subsystem’s compliance should not be allowed. Enabling the > cooling device also opens up the sysfs interface for userspace, which we may > not fully control. THere are a lot of interfaces exported to the userspace. > Userspace apps or partner apps might inadvertently use > it. Therefore, we believe it is better not to expose such an interface, as > it is not required for that SoC and helps to avoid opening up an interface > that could potentially lead to a safety failure. How can thermal mitigation interface lead to safety failure? Userspace can possibly lower trip points, but it can not override existing firmware-based mitigation. And if there is a known problem with the interface, it should be fixed instead. > > Best Regards, > > Manaf > > > -- With best wishes Dmitry
