linux-stable/drivers/pci
Abhishek Sahu 6d2e369f0d PCI: Add NVIDIA GPU multi-function power dependencies
The NVIDIA Turing GPU is a multi-function PCI device with the following
functions:

  - Function 0: VGA display controller
  - Function 1: Audio controller
  - Function 2: USB xHCI Host controller
  - Function 3: USB Type-C UCSI controller

Function 0 is tightly coupled with other functions in the hardware.  When
function 0 is in D3, it gates power for hardware blocks used by other
functions, which means those functions only work when function 0 is in D0.
If any of these functions (1/2/3) are in D0, then function 0 should also be
in D0.

Commit 07f4f97d7b ("vga_switcheroo: Use device link for HDA controller")
already creates a device link to show the dependency of function 1 on
function 0 of this GPU.  Create additional device links to express the
dependencies of functions 2 and 3 on function 0.  This means function 0
will be in D0 if any other function is in D0.

[bhelgaas: I think the PCI spec expectation is that functions can be
power-managed independently, so I don't think this device is technically
compliant.  For example, the PCIe r5.0 spec, sec 1.4, says "the PCI/PCIe
hardware/software model includes architectural constructs necessary to
discover, configure, and use a Function, without needing Function-specific
knowledge" and sec 5.1 says "D states are associated with a particular
Function" and "PM provides ... a mechanism to identify power management
capabilities of a given Function [and] the ability to transition a Function
into a certain power management state."]

Link: https://lore.kernel.org/lkml/20190606092225.17960-3-abhsahu@nvidia.com
Signed-off-by: Abhishek Sahu <abhsahu@nvidia.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2019-06-13 15:53:40 -05:00
..
controller pci-v5.2-changes 2019-05-14 10:30:10 -07:00
endpoint Merge branch 'remotes/lorenzo/pci/misc' 2019-05-13 18:34:44 -05:00
hotplug pci-v5.2-changes 2019-05-14 10:30:10 -07:00
pcie pci-v5.2-changes 2019-05-14 10:30:10 -07:00
switch pci-v5.2-changes 2019-05-14 10:30:10 -07:00
access.c PCI: Uninline PCI bus accessors for better ftracing 2018-10-04 16:37:37 -05:00
ats.c PCI/ATS: Add pci_ats_page_aligned() interface 2019-02-26 11:08:07 +01:00
bus.c PCI: Replace dev_printk(KERN_DEBUG) with dev_info(), etc 2019-05-09 07:49:58 -05:00
ecam.c
host-bridge.c
iov.c PCI/IOV: Add flag so platforms can skip VF scanning 2019-01-01 19:04:37 -06:00
irq.c
Kconfig PCI: Fix PCI kconfig menu organization 2019-01-14 17:01:20 -06:00
Makefile PCI: OF: Allow of_pci_get_max_link_speed() to be used by PCI Endpoint drivers 2019-04-15 13:24:02 +01:00
mmap.c
msi.c PCI: Add pci_dev_id() helper 2019-04-29 16:12:05 -05:00
of.c Merge branch 'remotes/lorenzo/pci/keystone' 2019-05-13 18:34:41 -05:00
p2pdma.c PCI/P2PDMA: Allow P2P DMA between any devices under AMD ZEN Root Complex 2019-05-01 16:53:39 -05:00
pci-acpi.c Merge branch 'pci/printk' 2019-05-13 18:34:46 -05:00
pci-bridge-emul.c PCI: pci-bridge-emul: Extend pci_bridge_emul_init() with flags 2019-02-22 10:51:14 +00:00
pci-bridge-emul.h PCI: pci-bridge-emul: Extend pci_bridge_emul_init() with flags 2019-02-22 10:51:14 +00:00
pci-driver.c Printk changes for 5.2 2019-05-07 09:18:12 -07:00
pci-label.c
pci-mid.c x86/cpu: Sanitize FAM6_ATOM naming 2018-10-02 10:14:32 +02:00
pci-pf-stub.c
pci-stub.c PCI: Replace printk(KERN_INFO) with pr_info(), etc 2019-05-09 07:49:54 -05:00
pci-sysfs.c PCI: Use dev_printk() when possible 2019-05-09 07:49:49 -05:00
pci.c pci-v5.2-changes 2019-05-14 10:30:10 -07:00
pci.h pci-v5.2-changes 2019-05-14 10:30:10 -07:00
probe.c pci-v5.2-changes 2019-05-14 10:30:10 -07:00
proc.c PCI: Mark expected switch fall-throughs 2019-03-20 15:11:11 -05:00
quirks.c PCI: Add NVIDIA GPU multi-function power dependencies 2019-06-13 15:53:40 -05:00
remove.c PCI/ASPM: Fix link_state teardown on device removal 2018-09-17 16:32:23 -05:00
rom.c
search.c PCI: Add pci_dev_id() helper 2019-04-29 16:12:05 -05:00
setup-bus.c Merge branch 'pci/trivial' 2019-05-13 18:34:48 -05:00
setup-irq.c
setup-res.c
slot.c PCI: Replace printk(KERN_INFO) with pr_info(), etc 2019-05-09 07:49:54 -05:00
syscall.c
vc.c
vpd.c
xen-pcifront.c Merge branch 'pci/printk' 2019-05-13 18:34:46 -05:00