Hi, On Thu, Apr 01, 2021 at 09:12:52PM +0800, Kai-Heng Feng wrote: > Built-in graphics on HP EliteDesk 805 G6 doesn't work because graphics > can't get the BAR it needs: > [ 0.611504] pci_bus 0000:00: root bus resource [mem 0x10020200000-0x100303fffff window] > [ 0.611505] pci_bus 0000:00: root bus resource [mem 0x10030400000-0x100401fffff window] > ... > [ 0.638083] pci 0000:00:08.1: bridge window [mem 0xd2000000-0xd23fffff] > [ 0.638086] pci 0000:00:08.1: bridge window [mem 0x10030000000-0x100401fffff 64bit pref] > [ 0.962086] pci 0000:00:08.1: can't claim BAR 15 [mem 0x10030000000-0x100401fffff 64bit pref]: no compatible bridge window > [ 0.962086] pci 0000:00:08.1: [mem 0x10030000000-0x100401fffff 64bit pref] clipped to [mem 0x10030000000-0x100303fffff 64bit pref] > [ 0.962086] pci 0000:00:08.1: bridge window [mem 0x10030000000-0x100303fffff 64bit pref] > [ 0.962086] pci 0000:07:00.0: can't claim BAR 0 [mem 0x10030000000-0x1003fffffff 64bit pref]: no compatible bridge window > [ 0.962086] pci 0000:07:00.0: can't claim BAR 2 [mem 0x10040000000-0x100401fffff 64bit pref]: no compatible bridge window > > However, the root bus has two contiguous regions that can contain the > child resource requested. > > Bjorn Helgaas pointed out that we can simply coalesce contiguous regions > for host bridges, since host bridge don't have _SRS. So do that > accordingly to make child resource can be contained. This change makes > the graphics works on the system in question. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212013 > Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> With this patch in place, I can no longer boot the ppc:sam460ex qemu emulation from nvme. I see the following boot error: nvme nvme0: Device not ready; aborting initialisation, CSTS=0x0 nvme nvme0: Removing after probe failure status: -19 A key difference seems to be swapped region addresses: ok: PCI host bridge to bus 0002:00^M pci_bus 0002:00: root bus resource [io 0x0000-0xffff] pci_bus 0002:00: root bus resource [mem 0xd80000000-0xdffffffff] (bus address [0x80000000-0xffffffff]) pci_bus 0002:00: root bus resource [mem 0xc0ee00000-0xc0eefffff] (bus address [0x00000000-0x000fffff]) bad: PCI host bridge to bus 0002:00^M pci_bus 0002:00: root bus resource [io 0x0000-0xffff] pci_bus 0002:00: root bus resource [mem 0xc0ee00000-0xc0eefffff] (bus address [0x00000000-0x000fffff]) pci_bus 0002:00: root bus resource [mem 0xd80000000-0xdffffffff] (bus address [0x80000000-0xffffffff]) and then bar address assignments are swapped/changed. ok: pci 0002:00:06.0: BAR 0: assigned [mem 0xd80000000-0xd83ffffff]^M pci 0002:00:06.0: BAR 1: assigned [mem 0xd84000000-0xd841fffff]^M pci 0002:00:02.0: BAR 0: assigned [mem 0xd84200000-0xd84203fff 64bit]^M pci 0002:00:01.0: BAR 5: assigned [mem 0xd84204000-0xd842041ff]^M pci 0002:00:03.0: BAR 0: assigned [io 0x1000-0x107f]^M pci 0002:00:03.0: BAR 1: assigned [mem 0xd84204200-0xd8420427f]^M pci 0002:00:01.0: BAR 4: assigned [io 0x1080-0x108f]^M pci 0002:00:01.0: BAR 0: assigned [io 0x1090-0x1097]^M pci 0002:00:01.0: BAR 2: assigned [io 0x1098-0x109f]^M pci 0002:00:01.0: BAR 1: assigned [io 0x10a0-0x10a3]^M pci 0002:00:01.0: BAR 3: assigned [io 0x10a4-0x10a7]^M pci_bus 0002:00: resource 4 [io 0x0000-0xffff]^M pci_bus 0002:00: resource 5 [mem 0xd80000000-0xdffffffff]^M pci_bus 0002:00: resource 6 [mem 0xc0ee00000-0xc0eefffff]^M bad: pci 0002:00:06.0: BAR 0: assigned [mem 0xd80000000-0xd83ffffff]^M pci 0002:00:06.0: BAR 1: assigned [mem 0xd84000000-0xd841fffff]^M pci 0002:00:02.0: BAR 0: assigned [mem 0xc0ee00000-0xc0ee03fff 64bit]^M pci 0002:00:01.0: BAR 5: assigned [mem 0xc0ee04000-0xc0ee041ff]^M pci 0002:00:03.0: BAR 0: assigned [io 0x1000-0x107f]^M pci 0002:00:03.0: BAR 1: assigned [mem 0xc0ee04200-0xc0ee0427f]^M pci 0002:00:01.0: BAR 4: assigned [io 0x1080-0x108f]^M pci 0002:00:01.0: BAR 0: assigned [io 0x1090-0x1097]^M pci 0002:00:01.0: BAR 2: assigned [io 0x1098-0x109f]^M pci 0002:00:01.0: BAR 1: assigned [io 0x10a0-0x10a3]^M pci 0002:00:01.0: BAR 3: assigned [io 0x10a4-0x10a7]^M pci_bus 0002:00: resource 4 [io 0x0000-0xffff]^M pci_bus 0002:00: resource 5 [mem 0xc0ee00000-0xc0eefffff]^M pci_bus 0002:00: resource 6 [mem 0xd80000000-0xdffffffff]^M Reverting this patch fixes the problem. Guenter --- bisect log: # bad: [f55966571d5eb2876a11e48e798b4592fa1ffbb7] Merge tag 'drm-next-2021-07-08-1' of git://anongit.freedesktop.org/drm/drm # good: [e9f1cbc0c4114880090c7a578117d3b9cf184ad4] Merge tag 'acpi-5.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm git bisect start 'f55966571d5e' 'e9f1cbc0c411' # bad: [b0dfd9af28b60d7ec42c359ae84c1ba97e093100] Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux git bisect bad b0dfd9af28b60d7ec42c359ae84c1ba97e093100 # bad: [364a716bd73e9846d3118a43f600f8f517658b38] Merge branch 'pci/host/intel-gw' git bisect bad 364a716bd73e9846d3118a43f600f8f517658b38 # good: [c9fb9042c98df94197a1ba4cf14a77c8053b0fae] Merge branch 'pci/p2pdma' git bisect good c9fb9042c98df94197a1ba4cf14a77c8053b0fae # bad: [7132700067f234d37c234e5d711bb49ea06d2352] Merge branch 'pci/sysfs' git bisect bad 7132700067f234d37c234e5d711bb49ea06d2352 # bad: [131e4f76c9ae9636046bf04d19d43af0e4ae9807] Merge branch 'pci/resource' git bisect bad 131e4f76c9ae9636046bf04d19d43af0e4ae9807 # good: [411e2a43d210e98730713acf6d01dcf823ee35e3] PCI: Work around Huawei Intelligent NIC VF FLR erratum git bisect good 411e2a43d210e98730713acf6d01dcf823ee35e3 # good: [e92605b0a0cdafb6c37b9d1ad24fe1cf8280eeb6] Merge branch 'pci/pm' git bisect good e92605b0a0cdafb6c37b9d1ad24fe1cf8280eeb6 # bad: [65db04053efea3f3e412a7e0cc599962999c96b4] PCI: Coalesce host bridge contiguous apertures git bisect bad 65db04053efea3f3e412a7e0cc599962999c96b4 # first bad commit: [65db04053efea3f3e412a7e0cc599962999c96b4] PCI: Coalesce host bridge contiguous apertures
