From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: andreas.noever@gmail.com, michael.jamet@intel.com,
YehezkelShB@gmail.com, sanju.mehta@amd.com,
mario.limonciello@amd.com, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] thunderbolt: Resume PCIe bridges after switch is found on AMD USB4 controller
Date: Mon, 5 Sep 2022 16:18:29 +0300 [thread overview]
Message-ID: <YxX3JeQLbciJ+hhc@black.fi.intel.com> (raw)
In-Reply-To: <YxWqSYDWe0NitSkL@black.fi.intel.com>
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():
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.
next prev parent reply other threads:[~2022-09-05 13:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-05 6:56 [PATCH] thunderbolt: Resume PCIe bridges after switch is found on AMD USB4 controller Kai-Heng Feng
2022-09-05 7:07 ` Mika Westerberg
2022-09-05 7:26 ` Kai-Heng Feng
2022-09-05 7:50 ` Mika Westerberg
2022-09-05 13:18 ` Mika Westerberg [this message]
2022-09-05 15:24 ` Kai-Heng Feng
2022-09-05 15:36 ` Mika Westerberg
2022-09-05 15:21 ` Kai-Heng Feng
2022-09-05 15:34 ` Mika Westerberg
2022-09-06 12:57 ` Kai-Heng Feng
2022-09-06 13:37 ` Mika Westerberg
2022-09-06 14:29 ` Kai-Heng Feng
2022-09-06 14:59 ` Mika Westerberg
2022-09-06 15:22 ` Mika Westerberg
2022-09-05 7:29 ` Greg KH
2022-09-07 16:30 ` Limonciello, Mario
2022-09-08 14:02 ` Kai-Heng Feng
2022-09-08 15:22 ` Limonciello, Mario
2022-09-12 7:35 ` Kai-Heng Feng
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