On Mon, 20 Oct 2025, Geert Uytterhoeven wrote: > On Fri, 10 Oct 2025 at 16:42, Ilpo Järvinen > wrote: > > Here's a series for Geert to test if this fixes the improper coalescing > > of resources as was experienced with the pci_add_resource() change (I > > know the breaking change was pulled before 6.18 main PR but I'd want to > > retry it later once the known issues have been addressed). The expected > > result is there'll be two adjacent host bridge resources in the > > resource tree as the different name should disallow coalescing them > > together, and therefore BAR0 has a window into which it belongs to. > > > > Generic info for the series: > > > > PCI host bridge windows were coalesced in place into one of the structs > > on the resources list. The host bridge window coalescing code does not > > know who holds references and still needs the struct resource it's > > coalescing from/to so it is safer to perform coalescing into entirely > > a new struct resource instead and leave the old resource addresses as > > they were. > > > > The checks when coalescing is allowed are also made stricter so that > > only resources that have identical the metadata can be coalesced. > > > > As a bonus, there's also a bit of framework to easily create kunit > > tests for resource tree functions (beyond just resource_coalesce()). > > > > Ilpo Järvinen (3): > > PCI: Refactor host bridge window coalescing loop to use prev > > PCI: Do not coalesce host bridge resource structs in place > > resource, kunit: add test case for resource_coalesce() > > Thanks for your series! > > I have applied this on top of commit 06b77d5647a4d6a7 ("PCI: > Mark resources IORESOURCE_UNSET when outside bridge windows"), and > gave it a a try on Koelsch (R-Car M2-W). So the pci_bus_add_resource() patch to rcar_pci_probe() was not included? No coalescing would be attempted without that change. With the pci_bus_add_resource() patch, the resource name is different, I think, so even then it should abort coalescing the ranges with this series. > Impact on dmesg (for the first PCI/USB) instance: > > pci-rcar-gen2 ee090000.pci: host bridge /soc/pci@ee090000 ranges: > pci-rcar-gen2 ee090000.pci: MEM 0x00ee080000..0x00ee08ffff > -> 0x00ee080000 > pci-rcar-gen2 ee090000.pci: PCI: revision 11 > pci-rcar-gen2 ee090000.pci: PCI host bridge to bus 0000:00 > pci_bus 0000:00: root bus resource [bus 00] > pci_bus 0000:00: root bus resource [mem 0xee080000-0xee08ffff] > pci 0000:00:00.0: [1033:0000] type 00 class 0x060000 conventional > PCI endpoint > -pci 0000:00:00.0: BAR 0 [mem 0xee090800-0xee090bff]: no initial > claim (no window) > pci 0000:00:00.0: BAR 0 [mem size 0x00000400] > -pci 0000:00:00.0: BAR 1 [mem 0x40000000-0x7fffffff pref]: no > initial claim (no window) > pci 0000:00:00.0: BAR 1 [mem size 0x40000000 pref] > pci 0000:00:01.0: [1033:0035] type 00 class 0x0c0310 conventional > PCI endpoint > -pci 0000:00:01.0: BAR 0 [mem 0x00000000-0x00000fff]: no initial > claim (no window) > pci 0000:00:01.0: BAR 0 [mem size 0x00001000] > pci 0000:00:01.0: supports D1 D2 > pci 0000:00:01.0: PME# supported from D0 D1 D2 D3hot > pci 0000:00:02.0: [1033:00e0] type 00 class 0x0c0320 conventional > PCI endpoint > -pci 0000:00:02.0: BAR 0 [mem 0x00000000-0x000000ff]: no initial > claim (no window) > pci 0000:00:02.0: BAR 0 [mem size 0x00000100] > pci 0000:00:02.0: supports D1 D2 > pci 0000:00:02.0: PME# supported from D0 D1 D2 D3hot > PCI: bus0: Fast back to back transfers disabled > pci 0000:00:01.0: BAR 0 [mem 0xee080000-0xee080fff]: assigned > pci 0000:00:02.0: BAR 0 [mem 0xee081000-0xee0810ff]: assigned > pci_bus 0000:00: resource 4 [mem 0xee080000-0xee08ffff] > pci 0000:00:01.0: enabling device (0140 -> 0142) > pci 0000:00:02.0: enabling device (0140 -> 0142) > > I.e. the "no initial claim (no window)" messages introduced by commit > 06b77d5647a4d6a7 are no longer seen. Is that perhaps again because of pci_dbg() vs pci_info()? > The BARs still show "mem size " instead of the "mem -" > before commit 06b77d5647a4d6a7, though. To me this looks like UNSET was still set for these resources. Missing the pci_bus_add_resource() patch would explain that and if the pci_dbg() wasn't printed, it would explain both symptoms. Once these questions are resolved, I'll ask Rob what is the preferred solution here, a) driver doing pci_bus_add_resource() or b) including it into the DT ranges (if we could fix the ranges). We likely need to go with a) to preserve backwards compatibility but I also want to understand how those ranges are supposed to be used if we wouldn't have historical baggage. (I appreciate following through even if the original series is now reverted!) > This series has not impact on /proc/iomem, or on the output of > "lspci -v" (commit 06b77d5647a4d6a7 also had no impact here). > I.e. the part of /proc/iomem related to the first PCI/USB instance > still looks like: > > ee080000-ee08ffff : pci@ee090000 > ee080000-ee080fff : 0000:00:01.0 > ee080000-ee080fff : ohci_hcd > ee081000-ee0810ff : 0000:00:02.0 > ee081000-ee0810ff : ehci_hcd > ee090000-ee090bff : ee090000.pci pci@ee090000 > > I hope this matches your expectation.s > > Gr{oetje,eeting}s, > > Geert > > -- i.