Re: [PATCH v3] PCI: Fix BAR resize for devices on a root bus

[email protected] Fri, 31 Jul 2026 17:48:38 +0000
Newsgroups org.kernel.vger.linux-pci
Message-ID <[email protected]>
> From: Liz Fong-Jones <[email protected]>
> 
> pci_do_resource_release_and_resize() releases the device BARs that
> share a bridge window with the BAR being resized, but when the device
> sits directly on a root bus (pdev->bus->self == NULL) it then skips
> resource assignment entirely and returns success, leaving the BARs it
> just released unassigned (IORESOURCE_UNSET).
> 
> Skipping pbus_reassign_bridge_resources() is correct in that case --
> there is no bridge window to adjust -- but the device BARs still have
> to be reassigned. Before the BAR release was consolidated into the PCI
> core, this case worked for amdgpu because the driver released the BARs
> itself and then called pci_assign_unassigned_bus_resources()
> unconditionally after the resize, which assigns unassigned device BARs
> also on a root bus. Commit db92e3fef53e ("drm/amdgpu: Remove driver
> [ ... ]
> Link: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-7.0/+bug/2159596
> Assisted-by: Claude:claude-fable-5 checkpatch
> Assisted-by: Claude:claude-sonnet-5
> Reviewed-by: Krzysztof Wilczyński <[email protected]>
> Signed-off-by: Liz Fong-Jones <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

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