Hi, On Mon, Dec 16, 2024 at 07:56:31PM +0200, Ilpo Järvinen wrote: > Resetting resource is problematic as it prevent attempting to allocate > the resource later, unless something in between restores the resource. > Similarly, if fail_head does not contain all resources that were reset, > those resource cannot be restored later. > > The entire reset/restore cycle adds complexity and leaving resources > into reseted state causes issues to other code such as for checks done > in pci_enable_resources(). Take a small step towards not resetting > resources by delaying reset until the end of resource assignment and > build failure list (fail_head) in sync with the reset to avoid leaving > behind resources that cannot be restored (for the case where the caller > provides fail_head in the first place to allow restore somewhere in the > callchain, as is not all callers pass non-NULL fail_head). > > The Expansion ROM check is temporarily left in place while building the > failure list until the upcoming change which reworks optional resource > handling. > > Ideally, whole resource reset could be removed but doing that in a big > step would make the impact non-tractable due to complexity of all > related code. > > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> With this patch in the mainline kernel, all mips:boston qemu emulations fail when running a 64-bit little endian configuration (64r6el_defconfig). The problem is that the PCI based IDE/ATA controller is not initialized. There are a number of pci error messages. pci_bus 0002:01: extended config space not accessible pci 0002:01:00.0: [8086:2922] type 00 class 0x010601 conventional PCI endpoint pci 0002:01:00.0: BAR 4 [io 0x0000-0x001f] pci 0002:01:00.0: BAR 5 [mem 0x00000000-0x00000fff] pci 0002:00:00.0: PCI bridge to [bus 01-ff] pci_bus 0002:01: busn_res: [bus 01-ff] end is updated to 01 pci 0002:00:00.0: bridge window [mem 0x16000000-0x160fffff]: assigned pci 0002:00:00.0: bridge window [mem size 0x00100000 64bit pref]: can't assign; no space pci 0002:00:00.0: bridge window [mem size 0x00100000 64bit pref]: failed to assign pci 0002:00:00.0: bridge window [io size 0x1000]: can't assign; no space pci 0002:00:00.0: bridge window [io size 0x1000]: failed to assign pci 0002:00:00.0: bridge window [mem size 0x00100000]: can't assign; bogus alignment pci 0002:00:00.0: bridge window [mem 0x16000000-0x160fffff 64bit pref]: assigned pci 0002:00:00.0: bridge window [io size 0x1000]: can't assign; no space pci 0002:00:00.0: bridge window [io size 0x1000]: failed to assign pci 0002:01:00.0: BAR 5 [mem size 0x00001000]: can't assign; no space pci 0002:01:00.0: BAR 5 [mem size 0x00001000]: failed to assign pci 0002:01:00.0: BAR 4 [io size 0x0020]: can't assign; no space pci 0002:01:00.0: BAR 4 [io size 0x0020]: failed to assign pci 0002:01:00.0: BAR 5 [mem size 0x00001000]: can't assign; no space pci 0002:01:00.0: BAR 5 [mem size 0x00001000]: failed to assign pci 0002:01:00.0: BAR 4 [io size 0x0020]: can't assign; no space pci 0002:01:00.0: BAR 4 [io size 0x0020]: failed to assign pci 0002:00:00.0: PCI bridge to [bus 01] pci 0002:00:00.0: bridge window [mem 0x16000000-0x160fffff 64bit pref] pci_bus 0002:00: Some PCI device resources are unassigned, try booting with pci=realloc pci_bus 0002:00: resource 4 [mem 0x16000000-0x160fffff] pci_bus 0002:01: resource 2 [mem 0x16000000-0x160fffff 64bit pref] ... pci 0002:00:00.0: enabling device (0000 -> 0002) ahci 0002:01:00.0: probe with driver ahci failed with error -12 Bisect points to this patch. Reverting it together with "PCI: Rework optional resource handling" fixes the problem. For comparison, after reverting the offending patches, the log messages are as follows. pci_bus 0002:00: root bus resource [bus 00-ff] pci_bus 0002:00: root bus resource [mem 0x16000000-0x160fffff] pci 0002:00:00.0: [10ee:7021] type 01 class 0x060400 PCIe Root Complex Integrated Endpoint pci 0002:00:00.0: PCI bridge to [bus 00] pci 0002:00:00.0: bridge window [io 0x0000-0x0fff] pci 0002:00:00.0: bridge window [mem 0x00000000-0x000fffff] pci 0002:00:00.0: bridge window [mem 0x00000000-0x000fffff 64bit pref] pci 0002:00:00.0: enabling Extended Tags pci 0002:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring pci_bus 0002:01: extended config space not accessible pci 0002:01:00.0: [8086:2922] type 00 class 0x010601 conventional PCI endpoint pci 0002:01:00.0: BAR 4 [io 0x0000-0x001f] pci 0002:01:00.0: BAR 5 [mem 0x00000000-0x00000fff] pci 0002:00:00.0: PCI bridge to [bus 01-ff] pci_bus 0002:01: busn_res: [bus 01-ff] end is updated to 01 pci 0002:00:00.0: bridge window [mem 0x16000000-0x160fffff]: assigned pci 0002:00:00.0: bridge window [mem size 0x00100000 64bit pref]: can't assign; no space pci 0002:00:00.0: bridge window [mem size 0x00100000 64bit pref]: failed to assign pci 0002:00:00.0: bridge window [io size 0x1000]: can't assign; no space pci 0002:00:00.0: bridge window [io size 0x1000]: failed to assign pci 0002:01:00.0: BAR 5 [mem 0x16000000-0x16000fff]: assigned pci 0002:01:00.0: BAR 4 [io size 0x0020]: can't assign; no space pci 0002:01:00.0: BAR 4 [io size 0x0020]: failed to assign pci 0002:00:00.0: PCI bridge to [bus 01] pci 0002:00:00.0: bridge window [mem 0x16000000-0x160fffff] pci_bus 0002:00: Some PCI device resources are unassigned, try booting with pci=realloc pci_bus 0002:00: resource 4 [mem 0x16000000-0x160fffff] pci_bus 0002:01: resource 1 [mem 0x16000000-0x160fffff] ... pci 0002:00:00.0: enabling device (0000 -> 0002) ahci 0002:01:00.0: enabling device (0000 -> 0002) ahci 0002:01:00.0: AHCI vers 0001.0000, 32 command slots, 1.5 Gbps, SATA mode ahci 0002:01:00.0: 6/6 ports implemented (port mask 0x3f) ahci 0002:01:00.0: flags: 64bit ncq only Bisect log is attached for reference. Guenter --- # bad: [609706855d90bcab6080ba2cd030b9af322a1f0c] Merge tag 'trace-latency-v6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace # good: [acb4f33713b9f6cadb6143f211714c343465411c] Merge tag 'm68knommu-for-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu git bisect start 'HEAD' 'acb4f33713b9' # good: [cf05922d63e2ae6a9b1b52ff5236a44c3b29f78c] Merge tag 'drm-intel-gt-next-2025-03-12' of https://gitlab.freedesktop.org/drm/i915/kernel into drm-next git bisect good cf05922d63e2ae6a9b1b52ff5236a44c3b29f78c # bad: [93d52288679e29aaa44a6f12d5a02e8a90e742c5] Merge tag 'backlight-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight git bisect bad 93d52288679e29aaa44a6f12d5a02e8a90e742c5 # bad: [e5e0e6bebef3a21081fd1057c40468d4cff1a60d] Merge tag 'v6.15-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 git bisect bad e5e0e6bebef3a21081fd1057c40468d4cff1a60d # bad: [dea140198b846f7432d78566b7b0b83979c72c2b] Merge branch 'pci/misc' git bisect bad dea140198b846f7432d78566b7b0b83979c72c2b # bad: [a113afb84ae63ec4c893bc3204945ef6f3bb89f7] Merge branch 'pci/endpoint' git bisect bad a113afb84ae63ec4c893bc3204945ef6f3bb89f7 # good: [a7a8e7996c1c114b50df5599229b1e7be38be3db] Merge branch 'pci/reset' git bisect good a7a8e7996c1c114b50df5599229b1e7be38be3db # bad: [7d4bcc0f2631e4ee10b5bcfff24a423d1c3c02a3] PCI: Move resource reassignment func declarations into pci/pci.h git bisect bad 7d4bcc0f2631e4ee10b5bcfff24a423d1c3c02a3 # good: [acba174d2e754346c07578ad2220258706a203e2] PCI: Use while loop and break instead of gotos git bisect good acba174d2e754346c07578ad2220258706a203e2 # good: [8884b5637b794ae541e8d6fb72102b1d8dba2b8d] PCI: Add debug print when releasing resources before retry git bisect good 8884b5637b794ae541e8d6fb72102b1d8dba2b8d # bad: [5af473941b56189423a7d16c05efabaf77299847] PCI: Increase Resizable BAR support from 512 GB to 128 TB git bisect bad 5af473941b56189423a7d16c05efabaf77299847 # bad: [96336ec702643aec2addb3b1cdb81d687fe362f0] PCI: Perform reset_resource() and build fail list in sync git bisect bad 96336ec702643aec2addb3b1cdb81d687fe362f0 # good: [e89df6d2beae847e931d84a190b192dfac41eba7] PCI: Use res->parent to check if resource is assigned git bisect good e89df6d2beae847e931d84a190b192dfac41eba7 # first bad commit: [96336ec702643aec2addb3b1cdb81d687fe362f0] PCI: Perform reset_resource() and build fail list in sync
