On Tuesday, October 1, 2019 12:00:50 PM CEST Karol Herbst wrote: > On Tue, Oct 1, 2019 at 11:11 AM Mika Westerberg > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > On Tue, Oct 01, 2019 at 10:56:39AM +0200, Karol Herbst wrote: > > > On Tue, Oct 1, 2019 at 10:47 AM Mika Westerberg > > > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > > > > > On Mon, Sep 30, 2019 at 06:36:12PM +0200, Karol Herbst wrote: > > > > > On Mon, Sep 30, 2019 at 6:30 PM Mika Westerberg > > > > > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > On Mon, Sep 30, 2019 at 06:05:14PM +0200, Karol Herbst wrote: > > > > > > > still happens with your patch applied. The machine simply gets shut down. > > > > > > > > > > > > > > dmesg can be found here: > > > > > > > https://gist.githubusercontent.com/karolherbst/40eb091c7b7b33ef993525de660f1a3b/raw/2380e31f566e93e5ba7c87ef545420965d4c492c/gistfile1.txt > > > > > > > > > > > > Looking your dmesg: > > > > > > > > > > > > Sep 30 17:24:27 kernel: nouveau 0000:01:00.0: DRM: DCB version 4.1 > > > > > > Sep 30 17:24:27 kernel: nouveau 0000:01:00.0: DRM: MM: using COPY for buffer copies > > > > > > Sep 30 17:24:27 kernel: [drm] Initialized nouveau 1.3.1 20120801 for 0000:01:00.0 on minor 1 > > > > > > > > > > > > I would assume it runtime suspends here. Then it wakes up because of PCI > > > > > > access from userspace: > > > > > > > > > > > > Sep 30 17:24:42 kernel: pci_raw_set_power_state: 56 callbacks suppressed > > > > > > > > > > > > and for some reason it does not get resumed properly. There are also few > > > > > > warnings from ACPI that might be relevant: > > > > > > > > > > > > Sep 30 17:24:27 kernel: ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20190509/nsarguments-59) > > > > > > Sep 30 17:24:27 kernel: ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20190509/nsarguments-59) > > > > > > > > > > > > > > > > afaik this is the case for essentially every laptop out there. > > > > > > > > OK, so they are harmless? > > > > > > > > > > yes > > > > > > > > > This seems to be Dell XPS 9560 which I think has been around some time > > > > > > already so I wonder why we only see issues now. Has it ever worked for > > > > > > you or maybe there is a regression that causes it to happen now? > > > > > > > > > > oh, it's broken since forever, we just tried to get more information > > > > > from Nvidia if they know what this is all about, but we got nothing > > > > > useful. > > > > > > > > > > We were also hoping to find a reliable fix or workaround we could have > > > > > inside nouveau to fix that as I think nouveau is the only driver > > > > > actually hit by this issue, but nothing turned out to be reliable > > > > > enough. > > > > > > > > Can't you just block runtime PM from the nouveau driver until this is > > > > understood better? That can be done by calling pm_runtime_forbid() (or > > > > not calling pm_runtime_allow() in the driver). Or in case of PCI driver > > > > you just don't decrease the reference count when probe() ends. > > > > > > > > > > the thing is, it does work for a lot of laptops. We could only observe > > > this on kaby lake and skylake ones. Even on Cannon Lakes it seems to > > > work just fine. > > > > Can't you then limit it to those? > > > > I've experienced that Kabylake root ports can enter and exit in D3cold > > just fine because we do that for Thunderbolt for example. But that > > always requires help from ACPI. If the system is using non-standard ACPI > > methods for example that may require some tricks in the driver side. > > > > yeah.. I am not quite sure what's actually the root cause. I was also > trying to use the same PCI registers ACPI is using to trigger this > issue on a normal desktop, no luck. Using the same registers does > trigger the issue (hence the script). > > The script is essentially just doing what ACPI does, just skipping a lot. > > > > > I think that would be much better than blocking any devices behind > > > > Kabylake PCIe root ports from entering D3 (I don't really think the > > > > problem is in the root ports itself but there is something we are > > > > missing when the NVIDIA GPU is put into D3cold or back from there). > > > > > > I highly doubt there is anything wrong with the GPU alone as we have > > > too many indications which tell us otherwise. > > > > > > Anyway, at this point I don't know where to look further for what's > > > actually wrong. And apparently it works on Windows, but I don't know > > > why and I have no idea what Windows does on such systems to make it > > > work reliably. > > > > By works you mean that Windows is able to put it into D3cold and back? > > If that's the case it may be that there is some ACPI magic that the > > Windows driver does and we of course are missing in Linux. > > Afaik that's the case. We were talking with Nvidia about it, but they > are not aware of any issues generally. (on Windows, nor the hardware). > No idea if we can trust their statements though. > > But yeah, it might be that on Windows they still do _DSM calls or > something... but until today, Nvidia didn't provide any documentation > to us for that. So IMO in that case the right approach is to quirk the combinations of GPU/root complex that are known problematic. Quirking the root complex alone is likely to affect working configurations which generally should be avoided.
