(cc'ing Lyude, who has the hw also I think). ----- Original Message ----- > From: "Peter Jones" <pjones@xxxxxxxxxx> > To: "Lukas Wunner" <lukas@xxxxxxxxx> > Cc: "David Airlie" <airlied@xxxxxxxxxx>, "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>, "Peter Wu" <peter@xxxxxxxxxxxxx>, > "Bjorn Helgaas" <helgaas@xxxxxxxxxx>, "Mika Westerberg" <mika.westerberg@xxxxxxxxxxxxxxx>, "Kilian Singer" > <kilian.singer@xxxxxxxxxxxxxxxxxxxxxx>, "linux-pci" <linux-pci@xxxxxxxxxxxxxxx>, "Alex Deucher" > <alexander.deucher@xxxxxxx>, "Hans de Goede" <hdegoede@xxxxxxxxxx> > Sent: Friday, 6 January, 2017 4:13:23 AM > Subject: Re: PCI: Revert "PCI: Add runtime PM support for PCIe ports" > > On Thu, Jan 05, 2017 at 04:06:46PM +0100, Lukas Wunner wrote: > > On Wed, Jan 04, 2017 at 06:21:14PM -0500, David Airlie wrote: > > > > On Wednesday, January 04, 2017 10:09:54 PM Peter Wu wrote: > > > > > On Wed, Jan 04, 2017 at 09:16:39AM +0100, Lukas Wunner wrote: > > > > > > On Tue, Jan 03, 2017 at 06:05:57PM -0600, Bjorn Helgaas wrote: > > > > > > > I don't *want* to apply the revert. It's on my for-linus branch > > > > > > > as a > > > > > > > worst-case scenario change if we can't figure out a better fix. > > > > > > > > > > > > > > The patch below is preferable, but I'd rather not take even it, > > > > > > > because it takes away functionality and forces people to use a > > > > > > > boot > > > > > > > parameter to restore it. I expect that somebody will figure out > > > > > > > how > > > > > > > to fix the regression Kilian found and also keep the new > > > > > > > functionality > > > > > > > (without requiring boot parameters) before v4.10. > > > > > > > > > > > > The issue is constrained to hybrid graphics laptops with Nvidia > > > > > > discrete > > > > > > GPU using nouveau. Hence it needs to be fixed in nouveau, not in > > > > > > the > > > > > > PCI core. > > > > > > > > > > The problem is not necessarily in the nouveau driver, the same > > > > > problem > > > > > occurs when you enable RPM without loading nouveau. The issue is > > > > > limited > > > > > though to some newer hybrid graphics laptops with Nvidia GPUs. While > > > > > a > > > > > quirk can be added to nouveau, I think that a (temporary) quirk in > > > > > core > > > > > would also be reasonable (since it also occurs without nouveau). > > > > > > > > > > > (AFAIUI, laptops with AMD discrete GPU are not affected as it is > > > > > > known > > > > > > when and how to call an ACPI method versus using PR3.) > > > > > > > > > > > > (Neither are laptops using the Nvidia proprietary driver as it > > > > > > doesn't > > > > > > runtime suspend the card. But battery life will be terrible then.) > > > > > > > > > > > > We're at rc2 so the time frame for coming up with a fix is probably > > > > > > 4 weeks. Peter and others have tried for months to > > > > > > reverse-engineer > > > > > > how to handle runtime PM on newer Nvidia cards. It seems likely > > > > > > that > > > > > > we'll not find the ultimate solution to the problem within 4 weeks. > > > > > > > > > > Yep, a quick proper fix seems unlikely. > > > > > [ Help/ideas are welcome, I suspect that these failures to restore > > > > > power > > > > > on laptops designed for Win8+ all have the same cause, related to > > > > > some > > > > > unknown interaction between ACPI and PCI. Some links: > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=190861 > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=156341 ] > > > > > > > > > > > The way it is now, i.e. defaulting to PR3 when available, regresses > > > > > > certain laptops such as Kilian's. If on the other hand we default > > > > > > to > > > > > > DSM when available, we'll regress certain other laptops, as Peter > > > > > > has > > > > > > pointed out. Whitelisting or blacklisting laptops doesn't seem a > > > > > > good > > > > > > approach either, ideally we'd want to use PR3 as Windows does. > > > > > > > > > > > > As said, the only short-term solution I see is to add an "optimus" > > > > > > module_param to nouveau to allow users to select which method to > > > > > > use. > > > > > > So in Kilian's case an additional command line parameter would be > > > > > > necessary to fix the issue. > > > > > > > > > > > > Does anyone see a better solution or can we agree on this one? If > > > > > > so > > > > > > I can come up with a patch. This could go in via Dave Airlie's > > > > > > tree. > > > > > > > > > > As pcie_port_pm=off already reverts to DSM, I do not think that an > > > > > additional (temporary) nouveau module parameter is going to help. I > > > > > instead propose a (hopefully temporary) quirk in pci core that > > > > > disables > > > > > D3cold RPM for just Kilians Lenovo laptop (basically defaulting to > > > > > pcie_port_pm=off). Then the option pcie_port_pm=force can still be > > > > > used > > > > > to test possible solutions in the future. > > > > > > > > I would rather add a quirk to the ACPI core to prevent the power > > > > resources in > > > > question from being enumerated. Or even to prevent ACPI PM from being > > > > used for the port in question. > > > > > > I do have a W541 in a cupboard in the office somewhere, but I won't be > > > close to > > > it for a couple of weeks. The W541 was the first place I tested the pm > > > patches > > > so I'm kinda wondering whether it's all W541's or just some specific > > > model/bios > > > combo. > > They seem to all ship with the 1.10 firmware, and 2.80 is current (there > are a bunch of intermediate 2.xx versions). Somewhere along the line > they introduced some bugs in the UEFI stuff, so it wouldn't be > surprising if there's bugs introduced elsewhere as well. > > > > However I'm pretty much unavailable to do anything much until late Jan on > > > this. > > > > Is there anyone else at Red Hat who might be able to look into this? > > > > ISTR that Hans de Goede is working on improving laptop support in Fedora, > > and Peter Jones recently got a patch merged for the W541 with the exact > > same firmware Kilian is using to work around a botched EFI memory map. > > Adding them to cc: in the hope that they may be able to help. > > > > @Peter, have you noticed issues with the discrete Nvidia GPU on your W541 > > related to runtime suspend and system sleep? > > I was using a borrowed one (I can certainly find it again, but I'm not > working on graphics/pm really), but yeah - shutdown and lspci both broke > sometime after pci_pm_runtime_resume(). Here's the traceback from > SYS_reboot(): https://goo.gl/photos/T1fr1bksHQb9RSU67 > > Dave, if you know who in Westford should have a look at this, I can see > about getting them hardware. I am more or less surrounded by that team. > > -- > Peter > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
