JIRA: https://issues.redhat.com/browse/RHEL-47438
Upstream Status: d66041063192497a4a97d21dbf86b79a03a7f4fb
commit d66041063192497a4a97d21dbf86b79a03a7f4fb
Author: Jian-Hong Pan <jhp@endlessos.org>
Date: Tue Oct 1 16:34:38 2024 +0800
PCI: vmd: Set devices to D0 before enabling PM L1 Substates
The remapped PCIe Root Port and the child device have PM L1 Substates
capability, but they are disabled originally.
Here is a failed example on ASUS B1400CEAE:
Capabilities: [900 v1] L1 PM Substates
L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1- L1_PM_Substates+
PortCommonModeRestoreTime=32us PortTPowerOnTime=10us
L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1-
T_CommonMode=0us LTR1.2_Threshold=101376ns
L1SubCtl2: T_PwrOn=50us
Enable PCI-PM L1 PM Substates for devices below VMD while they are in D0
(see PCIe r6.0, sec 5.5.4).
Link: https://lore.kernel.org/r/20241001083438.10070-4-jhp@endlessos.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Myron Stowe <mstowe@redhat.com>
aa818221c0