Hi, On 8/12/22 10:31, Thomas Weißschuh wrote: > Hi, > > On 2022-08-12 09:59+0200, Hans de Goede wrote: >> Date: Fri, 12 Aug 2022 09:59:29 +0200 >> From: Hans de Goede <hdegoede@xxxxxxxxxx> >> To: Luke Jones <luke@xxxxxxxxxx> >> Cc: andy.shevchenko@xxxxxxxxx, pobrn@xxxxxxxxxxxxxx, pavel@xxxxxx, >> platform-driver-x86@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx >> Subject: Re: [PATCH v3 6/6] asus-wmi: Support the hardware GPU MUX on some >> laptops >> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 >> Thunderbird/91.12.0 >> >> Hi, >> >> On 8/12/22 00:01, Luke Jones wrote: >>> Hi Hans, >>> >>> On Thu, 2022-08-11 at 15:53 +0200, Hans de Goede wrote: >>>> Hi, >>>> >>>> On 8/9/22 04:50, Luke D. Jones wrote: >>>>> Support the hardware GPU MUX switch available on some models. This >>>>> switch can toggle the MUX between: >>>>> >>>>> - 0, Dedicated mode >>>>> - 1, Optimus mode >>>>> >>>>> Optimus mode is the regular iGPU + dGPU available, while dedicated >>>>> mode switches the system to have only the dGPU available. >>>>> >>>>> Signed-off-by: Luke D. Jones <luke@xxxxxxxxxx> >>>> >>>> I see that you have replied to this that it needs more work. >>>> >>>> Besides it needing more work, ideally this should hook into >>>> the existing vga-switcheroo mechanism for this. Can you take >>>> a look at that please? >>>> >>>> I think this might be the first non GPU driver doing vga- >>>> switcheroo stuff. So this may be something to discuss >>>> on the dri-devel list. >>> >>> I'm not sure how this would work. In typical ASUS fashion they do non- >>> standard stuff. This switch is a basic toggle that requires a reboot to >>> enable after writing to the ACPI method, after reboot the dGPU becomes >>> the only visible GPU on the system and (this GPU) can not be suspended. >>> >>> In short: it toggles the laptop from discrete-only mode, and optimus >>> mode, requiring a reboot to switch. >>> >>> From what I understand of switcheroo it is more to manage having dual >>> (or more) GPU available during runtime, and manage the power states, >>> offload etc. >> >> Right, I did not realize this requires a reboot, that would be >> something to mention in the Documentation bits accompanying the patch. >> >> This is also a reason why it is good to have the docs update in >> the same patch as adding the functionality, because the docs may >> help with reviewing. >> >> Anyways I agree that if this requires a reboot then using >> the vga switcheroo stuff is not applicable. So we can just go with >> a simple(ish) asus-wmi sysfs attribute. > > Would this not fit the existing "firmware-attributes" class? > It even has a flag to signal that a reboot is required after an attribute has > been changed. Yes it sounds like a BIOS setting is being toggled from within Linux, which would normally be done through the "firmware-attributes" class, but all existing "firmware-attributes" class drivers allow changing all BIOS setting not just a single setting, so using the "firmware-attributes" class here is not really appropriate. > Maybe it is overkill to use it only for this, though. Right :) Regards, Hans >>> I have a vastly improved patch for this prepared now. Because of how >>> the actual feature works (and the above explanation) it must be under >>> the asus-nb-wmi sysfs (next to the dgpu_disable and egpu_enable toggles >>> which are also unusual and non-standard work-arounds of Windows >>> issues). >> >> Ack, sounds good. > > Thomas >
