From: Sebastian Ott <sebott@redhat.com>
To: qemu-devel@nongnu.org
Cc: Alex Williamson <alex.williamson@redhat.com>,
Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
"Michael S . Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH] pci: ensure valid link status bits for downstream ports
Date: Mon, 11 Nov 2024 13:40:59 +0100 (CET) [thread overview]
Message-ID: <0a0049d2-7c72-5e5b-c35f-d777418f3eaa@redhat.com> (raw)
In-Reply-To: <20241111123756.18393-1-sebott@redhat.com>
On Mon, 11 Nov 2024, Sebastian Ott wrote:
> PCI hotplug for downstream endpoints on arm fails because Linux'
> PCIe hotplug driver doesn't like the QEMU provided LNKSTA:
>
> pcieport 0000:08:01.0: pciehp: Slot(2): Card present
> pcieport 0000:08:01.0: pciehp: Slot(2): Link Up
> pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000
>
> There's 2 cases where LNKSTA isn't setup properly:
> * the downstream device has no express capability
I stumbled over this while debugging - is a pci device attached
to a pcie downstream even a valid usecase?
> * max link width of the bridge is 0
MLW for the downstream is initialized with defaults but gets overwritten
later because speed and width properties are 0. Dunno if that's the issue
we should address?
Sebastian
next prev parent reply other threads:[~2024-11-11 12:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-11 12:37 [PATCH] pci: ensure valid link status bits for downstream ports Sebastian Ott
2024-11-11 12:40 ` Sebastian Ott [this message]
2024-11-15 12:42 ` Zhenyu Zhang
2024-11-21 11:08 ` Sebastian Ott
2024-12-02 19:03 ` Alex Williamson
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