Re: [PATCH v2 1/2] PCI: Ignore Immediate Readiness on Samsung 990 PRO NVMe

[Lukas Wunner]

On Sun, Oct 11, 2026 at 06:32:48PM +0200, Alexander Gruhlke wrote:
> The Samsung 990 PRO [144d:a80c] advertises Immediate Readiness, so
> pcie_flr() doesn't wait after FLR, but the drive returns ~0 for up to
> 7 ms.  Since commit 10baa9b4df40 ("PCI: Drop unnecessary retries when
> restoring BARs"), the config restore after FLR is lost, which breaks
> VFIO passthrough of the drive.  Firmware 8B2QJXD7 responds right after
> FLR, but older firmware such as 1B2QJXD7 doesn't, and the firmware
> version isn't visible here.

If a firmware update is available from the vendor, we generally
refrain from adding a quirk and instead tell users to update.

OTOH, the offending patch breaks setups that worked before,
which is annoying.

It's also a bit of a bummer that the quirk can't check the
firmware version.  Has the upgrade changed the Revision ID
in the Config Space header?  If it did, that could be used
to identiy non-broken devices, but usually it's only incremented
for new silicon revisions.

Up to Bjorn what to do here.

FWIW,
Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>