On Mon, Sep 5, 2022 at 9:18 PM Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > Hi, > > On Mon, Sep 05, 2022 at 10:50:33AM +0300, Mika Westerberg wrote: > > > Yes those root ports are resumed to D0 when something is plugged. They > > > however fail to detect any externel PCIe devices. > > > > Hmm, so you see the actual hotplug but the tunneled PCIe link may not be > > detected? Does the PCIe "Card Present" (or Data Link Layer Active) > > status change at all or is it always 0? > > I wonder if we are simply missing the required delays here? Looking at > the lspci dump in the bugzilla you refer the root port 03.1 supports > active link reporting: > > LnkCap: Port #247, Speed 2.5GT/s, Width x1, ASPM L1, Exit Latency L1 <4us > ClockPM- Surprise- LLActRep+ BwNot- ASPMOptComp+ > > So when the link goes back to L0 (D3 -> D0 transition) the kernel should > issue the 100+ ms reset delay in pci_bridge_wait_for_secondary_bus(): This was actually the first thing I tried but it doesn't work. Even a 5 seconds delay doesn't work either. > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/pci.c#n5045 > > can you check if that is happening? It should show up in the dmesg when > CONFIG_PCI_DEBUG=y but I don't see it in yours. That's because there isn't any child device yet, so the function bails early: if (!dev->subordinate || list_empty(&dev->subordinate->devices)) Kai-Heng
