On Thu, Dec 2, 2021 at 4:05 AM Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: > > When Samsung PCIe Gen4 NVMe is connected to Intel ADL VMD, the > combination causes AER message flood and drags the system performance > down. > > The issue doesn't happen when VMD mode is disabled in BIOS, since AER > isn't enabled by acpi_pci_root_create() . When VMD mode is enabled, AER > is enabled regardless of _OSC: > [ 0.410076] acpi PNP0A08:00: _OSC: platform does not support [AER] > ... > [ 1.486704] pcieport 10000:e0:06.0: AER: enabled with IRQ 146 > > Since VMD is an aperture to regular PCIe root ports, honor ACPI _OSC to > disable PCIe features accordingly to resolve the issue. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215027 > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > v2: > - Use pci_find_host_bridge() instead of open coding. > > drivers/pci/controller/vmd.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c > index a45e8e59d3d48..acf847cb825c0 100644 > --- a/drivers/pci/controller/vmd.c > +++ b/drivers/pci/controller/vmd.c > @@ -671,6 +671,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) > resource_size_t offset[2] = {0}; > resource_size_t membar2_offset = 0x2000; > struct pci_bus *child; > + struct pci_host_bridge *root_bridge, *vmd_bridge; > int ret; > > /* > @@ -798,6 +799,17 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) > return -ENODEV; > } > > + vmd_bridge = to_pci_host_bridge(vmd->bus->bridge); > + > + root_bridge = pci_find_host_bridge(vmd->dev->bus); > + > + vmd_bridge->native_pcie_hotplug = root_bridge->native_pcie_hotplug; > + vmd_bridge->native_shpc_hotplug = root_bridge->native_shpc_hotplug; > + vmd_bridge->native_aer = root_bridge->native_aer; > + vmd_bridge->native_pme = root_bridge->native_pme; > + vmd_bridge->native_ltr = root_bridge->native_ltr; > + vmd_bridge->native_dpc = root_bridge->native_dpc; One more, arguably minor, thing: I would put the above copying into a separate function and call it here and I would add a comment explaining why it is done next to it, like /* * Since VMD is an aperture to regular PCIe root ports, only allow it to control * features that the OS is allowed to control on the physical PCI bus. */ vmd_copy_host_bridge_flags(to_pci_host_bridge(vmd->bus->bridge), pci_find_host_bridge(vmd->dev->bus)); > + > vmd_attach_resources(vmd); > if (vmd->irq_domain) > dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); > -- > 2.32.0 >
