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From: Limonciello, M. <Mar...@de...> - 2020-08-21 20:01:02
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> -----Original Message----- > From: pla...@vg... <platform-driver-x86- > ow...@vg...> On Behalf Of Mark Pearson > Sent: Friday, August 21, 2020 14:36 > To: Limonciello, Mario > Cc: ibm...@li...; pla...@vg...; > ibm...@hm...; bn...@re...; Nitin Joshi > Subject: Re: [External] RE: [PATCH v2] platform/x86: thinkpad_acpi: > performance mode interface > > > [EXTERNAL EMAIL] > > Hi Mario > > On 8/21/2020 3:15 PM, Limonciello, Mario wrote: > >> > <snip> > > > > Thanks for adapting a lot of my feedback, this looks much better to me. > > > No problems and genuinely thank you for the feedback. Sorry it took so > long to get this update out - PTO and other things got in the way :) > > >> > <snip> > >> + > >> +The sysfs entry provides the ability to return the current status and to > set > >> the > >> +desired mode. For example:: > >> + > >> + echo H > /sys/devices/platform/thinkpad_acpi/dytc_perfmode > >> + echo M > /sys/devices/platform/thinkpad_acpi/dytc_perfmode > >> + echo L > /sys/devices/platform/thinkpad_acpi/dytc_perfmode > >> + > > > > I was thinking about this some more, do you actually want another mode that > "disables" > > this feature? IE "O" turns it off an calls DYTC_DISABLE_CQL. > > > > For example if a user wanted to test the recently landed code in thermald > 2.3 > > and compare performance between the two it seems like this and that "might" > fight. > > As an outsider looking in - I of course may be wrong too here. > > > > If at some point in the future thermald does a better job than this > implementation you > > might also want an "out" to let thermald or another piece of userland turn > this off > > if it's in the picture. > > > I'm still digging into this one. Right now I haven't found a good clean > way of just disabling the firmware. Currently when thermald goes in and > tweaks the CPU power registers it has the effect of overriding the FW > anyway - but I appreciate that's not quite the same as actually doing it > explicitly. > What about a modprobe parameter to disable at least? That would at least make it pretty easy to make a change, reboot and compare with thermald (or other software) without disabling the rest of the functionality of the thinkpad_acpi driver. > I'm still discussing with the BIOS team how to implement this - these > conversations take time.... I suspect I'll need a new BIOS API which > will take a while to implement and get rolled out. I didn't want to hold > up this patch as there are benefits for users in the meantime and Lenovo > do plan on supporting the thermal software going forwards. I'm not not > dropping the plan to have a disable function as I can see the benefits. > Yup, well aware how these types of things go. > Thanks for the input. Let me know if you want a reviewed-by tag added. I > think it's kinda awesome having input from a Dell engineer on a Lenovo > related driver and I hope in the future I can provide the same help ;) > Open source is awesome. > > Mark 😊 |
