> -----Original Message----- > From: Peter Wu [mailto:peter@xxxxxxxxxxxxx] > Sent: Tuesday, January 03, 2017 11:32 AM > To: Lukas Wunner > Cc: Mika Westerberg; Rafael J. Wysocki; Kilian Singer; Bjorn Helgaas; linux-pci; > Deucher, Alexander; Dave Airlie > Subject: Re: PCI: Revert "PCI: Add runtime PM support for PCIe ports" > > On Tue, Jan 03, 2017 at 05:11:23PM +0100, Lukas Wunner wrote: > > [cc += Dave Airlie: > > > > Dave, we're about to lose support for newer Optimus laptops which use > > _PR3 to cut power to the discrete GPU because Bjorn Helgaas has queued > > a commit on his for-linus branch to remove runtime PM for PCIe ports. > > This fixes a regression on Kilian Singer's laptop on which locking the > > screen breaks USB and PS/2 input devices: Mouse movements are still > > visible, but button or key presses no longer have any effect. The GPU > > is powered down upon locking the screen and the current theory is that > > this causes the issues.] > > (+cc Alex: this might affect amdgpu/radeon too.] > > Bjorn, please reconsider the rpm patch. Reverting support would > introduce other regressions (see issues below) and make future > Thunderbolt work harder (according to Lukas). If Kilian's laptop has > issues, what about a "temporary" quirk? > > > On Tue, Jan 03, 2017 at 04:15:47PM +0100, Peter Wu wrote: > > > The acpidump from the bug does not show known issues, it *looks* fine. > > > There have been other issues related to resuming power on newer > Nvidia > > > hardware (https://bugs.freedesktop.org/show_bug.cgi?id=94725, > > > https://bugzilla.kernel.org/show_bug.cgi?id=156341) but there is not > > > much progress here. (The last time I traced the PCIe register accesses > > > (via kprobes) and tried to disable some of those, it still did not help > > > with preventing the power issue.) > > > > It seems that the _DSM method works on Kilian's laptop. Would it be > > viable to default to _DSM if it's available, and only use _PR3 if not? > > DSM should not be preferred when PR3 is available: > > - After MS introduced D3cold (PR3) support to Win8+, vendors are > unlikely to test legacy DSM and the likelihood of breakage increases. > - On one Lenovo laptop, the DSM method causes memory corruption while > PR3 fixes this problem. > - On some laptops, DSM keeps the fan on while PR3 stopped the noise. > - On some laptops, DSM does not really power off the GPU and results in > increased power consumption during runtime/system sleep. PR3 fully > removes the power, as desired. Yes, this will affect just about all AMD multi-GPU laptops from late 2013 onward. I'd much prefer a temporary quirk for this specific laptop than to disable PR3 for everything. Alex > -- > Kind regards, > Peter Wu > https://lekensteyn.nl -- 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
