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7180c1d086("PCI: Distribute available resources for root buses, too") breaks BAR assignment on some devices: pci 0006:03:00.0: BAR 0 [mem 0x6300c0000000-0x6300c1ffffff 64bit pref]: assigned pci 0006:03:00.1: BAR 0 [mem 0x6300c2000000-0x6300c3ffffff 64bit pref]: assigned pci 0006:03:00.2: BAR 0 [mem size 0x00800000 64bit pref]: can't assign; no space pci 0006:03:00.0: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space pci 0006:03:00.1: VF BAR 0 [mem size 0x02000000 64bit pref]: can't assign; no space The apertures of domain 0006 before7180c1d086: 6300c0000000-63ffffffffff : PCI Bus 0006:00 6300c0000000-6300c9ffffff : PCI Bus 0006:01 6300c0000000-6300c9ffffff : PCI Bus 0006:02 # 160MB 6300c0000000-6300c8ffffff : PCI Bus 0006:03 # 144MB 6300c0000000-6300c1ffffff : 0006:03:00.0 # 32MB 6300c2000000-6300c3ffffff : 0006:03:00.1 # 32MB 6300c4000000-6300c47fffff : 0006:03:00.2 # 8MB 6300c4800000-6300c67fffff : 0006:03:00.0 # 32MB 6300c6800000-6300c87fffff : 0006:03:00.1 # 32MB 6300c9000000-6300c9bfffff : PCI Bus 0006:04 # 12MB 6300c9000000-6300c9bfffff : PCI Bus 0006:05 # 12MB 6300c9000000-6300c91fffff : PCI Bus 0006:06 # 2MB 6300c9200000-6300c93fffff : PCI Bus 0006:07 # 2MB 6300c9400000-6300c95fffff : PCI Bus 0006:08 # 2MB 6300c9600000-6300c97fffff : PCI Bus 0006:09 # 2MB After7180c1d086: 6300c0000000-63ffffffffff : PCI Bus 0006:00 6300c0000000-6300c9ffffff : PCI Bus 0006:01 6300c0000000-6300c9ffffff : PCI Bus 0006:02 # 160MB 6300c0000000-6300c43fffff : PCI Bus 0006:03 # 68MB 6300c0000000-6300c1ffffff : 0006:03:00.0 # 32MB 6300c2000000-6300c3ffffff : 0006:03:00.1 # 32MB --- no space --- : 0006:03:00.2 # 8MB --- no space --- : 0006:03:00.0 # 32MB --- no space --- : 0006:03:00.1 # 32MB 6300c4400000-6300c4dfffff : PCI Bus 0006:04 # 10MB 6300c4400000-6300c4dfffff : PCI Bus 0006:05 # 10MB 6300c4400000-6300c45fffff : PCI Bus 0006:06 # 2MB 6300c4600000-6300c47fffff : PCI Bus 0006:07 # 2MB 6300c4800000-6300c49fffff : PCI Bus 0006:08 # 2MB 6300c4a00000-6300c4bfffff : PCI Bus 0006:09 # 2MB We can see that the window to 0006:03 gets shrunken too much and 0006:04 eats away the window for 0006:03:00.2. The offending commit distributes the upstream bridge's resources multiple times to every downstream bridge, hence makes the aperture smaller than desired because calculation of io_per_b, mmio_per_b and mmio_pref_per_b becomes incorrect. Instead, distribute downstream bridges' own resources to resolve the issue. Link: https://lore.kernel.org/r/20241204022457.51322-1-kaihengf@nvidia.com Fixes:7180c1d086("PCI: Distribute available resources for root buses, too") Link: https://bugzilla.kernel.org/show_bug.cgi?id=219540 Signed-off-by: Kai-Heng Feng <kaihengf@nvidia.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Carol Soto <csoto@nvidia.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Chris Chiu <chris.chiu@canonical.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.