On 6/15/23 12:04 AM, Kai-Heng Feng wrote: > When a PCIe device is hotplugged to a Thunderbolt port, ASPM is not > enabled for that device. However, when the device is plugged preboot, > ASPM is enabled by default. > > The disparity happens because BIOS doesn't have the ability to program > ASPM on hotplugged devices. > > So enable ASPM by default for external connected PCIe devices so ASPM > settings are consitent between preboot and hotplugged. Why it has to be consistent? Can you add info about what it solves? > > On HP Thunderbolt Dock G4, enable ASPM can also fix BadDLLP error: > pcieport 0000:00:1d.0: AER: Corrected error received: 0000:07:04.0 > pcieport 0000:07:04.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver ID) > pcieport 0000:07:04.0: device [8086:0b26] error status/mask=00000080/00002000 > pcieport 0000:07:04.0: [ 7] BadDLLP > > The root cause is still unclear, but quite likely because the I225 on > the dock supports PTM, where ASPM timing is precalculated for the PTM. > > Cc: Mario Limonciello <mario.limonciello@xxxxxxx> > Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=217557 > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > drivers/pci/pcie/aspm.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index 66d7514ca111..613b0754c9bb 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -119,7 +119,9 @@ static int policy_to_aspm_state(struct pcie_link_state *link) > /* Enable Everything */ > return ASPM_STATE_ALL; > case POLICY_DEFAULT: > - return link->aspm_default; > + return dev_is_removable(&link->downstream->dev) ? > + link->aspm_capable : > + link->aspm_default; > } > return 0; > } -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
