On Tue, Jun 25, 2019 at 12:30 PM Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > Hi all, > > This is third iteration of the patch series addressing issues around > sibling PCI devices sharing ACPI power resources. > > As a concrete example in Intel Ice Lake the Thunderbolt controller, PCIe > root ports and xHCI all share the same ACPI power resources. When they are > all in D3hot power resources (returned by _PR3) can be turned off powering > off the whole block. However, there are two issues around this. > > Firstly the PCI core sets the device power state by asking what the real > ACPI power state is. This results that all but last device sharing the > power resources are in D3hot when the power resources are turned off. This > causes issues if user runs for example 'lspci' because the device is really > in D3cold so what user gets back is all ones (0xffffffff). > > Secondly if any of the device is runtime resumed the power resources are > turned on bringing all other devices sharing the resources to > D0uninitialized losing their wakeup configuration. > > This series aims to fix the two issues by: > > 1. Using the ACPI cached power state when PCI devices are transitioned > into low power states instead of reading back the "real" power state. > > 2. Introducing concept of "_PR0 dependent devices" that get runtime > resumed whenever their power resource (which they might share with > other sibling devices) gets turned on. > > The series is based on the idea of Rafael J. Wysocki <rafael@xxxxxxxxxx>. > > Previous version of the series can be found here: > > v2: https://lore.kernel.org/linux-pci/20190618161858.77834-1-mika.westerberg@xxxxxxxxxxxxxxx/T/#m7a41d0b745400054543324ce84125040dbfed912 > v1: https://www.spinics.net/lists/linux-pci/msg83583.html > > Changes from v2: > > * Updated changelog of patch [1/3] according to comments I got. I left > the D3C power resource and xHCI there because it shows that we can have > multiple shared power resources. > > * Added link to the discussion around v2. > > * Use adev->flags.power_manageable in patch [2/3]. > > Mika Westerberg (3): > PCI / ACPI: Use cached ACPI device state to get PCI device power state > ACPI / PM: Introduce concept of a _PR0 dependent device > PCI / ACPI: Add _PR0 dependent devices > > drivers/acpi/power.c | 135 ++++++++++++++++++++++++++++++++++++++++ > drivers/pci/pci-acpi.c | 5 +- > include/acpi/acpi_bus.h | 4 ++ > 3 files changed, 143 insertions(+), 1 deletion(-) > The whole series looks good to me, thank you!
