Re: [PATCH v6 0/3] PCI: distribute resources for root buses

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Jan 31, 2023 at 11:24:02AM +0200, Mika Westerberg wrote:
> Hi all,
> 
> This is sixth iteration of the patch series trying to solve the problem
> reported by Chris Chiu [1]. In summary the current resource distribution
> code does not cover the initial device enumeration so if we find
> unconfigured bridges they get the bare minimum.
> 
> In addition to that it turned out the current resource distribution code
> does not take into account possible multifunction devices and/or other
> devices on the bus. The patch 1/2 tries to make it more generic. I've
> tested it on QEMU following the topology Jonathan is using and also in a
> a couple of systems with Thunderbolt controller and complex topologies
> to make sure it still keeps working.
> 
> The previous versions of the series can be found:
> 
> v5: https://lore.kernel.org/linux-pci/20230112110000.59974-1-mika.westerberg@linux.intel.com/
> v4: https://lore.kernel.org/linux-pci/20230104091635.63331-1-mika.westerberg@linux.intel.com/
> v3: https://lore.kernel.org/linux-pci/20221130112221.66612-1-mika.westerberg@linux.intel.com/
> v2: https://lore.kernel.org/linux-pci/20221114115953.40236-1-mika.westerberg@linux.intel.com/
> v1: https://lore.kernel.org/linux-pci/20221103103254.30497-1-mika.westerberg@linux.intel.com/
> 
> Changes from v5:
>   * Correct typo in mmio calculation (io_per_hp -> mmio_per_hp)
>   * Add missing -1 to the mmio_pref end when align == 0.
> 
> Changes from v4:
>   * Split the alignment fix into separate patch
>   * Create helper for removing resources
>   * Skip VF BARs when removing
>   * Add check for 32-bit/64-bit prefetchable resource so that we account
>     them correctly.
>   * Update comments and commit log slightly according to review
>     comments.
>   * Did not add the "lookup for hotplug bridges below non-hotplug ones".
>     It turned out to be non-trivial. The current code works for the
>     "common" case of Thunderbolt/USB4 PCIe switches but we may need to
>     revisit this if there is a real need.
> 
> Changes from v3:
>   * Make it more generic and not depend on how many bridges there are
>     on the bus.
> 
> Changes from v2:
>   * Make both patches to work with PCI devices too (do not expect that
>     the bridge is always first device on the bus).
>   * Allow distribution with bridges that do not have all resource
>     windows programmed (therefore the patch 2/2 is not revert anymore)
>   * I did not add the tags from Rafael and Jonathan because the code is
>     not exactly the same anymore so was not sure if they still apply.
> 
> Changes from v1:
>   * Re-worded the commit message to hopefully explain the problem better
>   * Added Link: to the bug report
>   * Update the comment according to Bjorn's suggestion
>   * Dropped the ->multifunction check
>   * Use %#llx in log format.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=216000
> 
> Mika Westerberg (3):
>   PCI: Align extra resources for hotplug bridges properly
>   PCI: Take other bus devices into account when distributing resources
>   PCI: Distribute available resources for root buses too
> 
>  drivers/pci/setup-bus.c | 232 ++++++++++++++++++++++++++++------------
>  1 file changed, 166 insertions(+), 66 deletions(-)

Applied to pci/resource for v6.3, thanks, Mika!