Created attachment 306293 [details] dmesg output containing the problem When I start my Dell XPS 16 9640 (2024) with a 6.9.0 mainline kernel, I am missing a CPU core: LC_ALL=C lscpu --all --extended CPU NODE SOCKET CORE ONLINE MAXMHZ MINMHZ MHZ 0 0 0 0 yes 4800.0000 400.0000 2000.0000 1 0 0 1 yes 5100.0000 400.0000 3800.0000 2 0 0 2 yes 5100.0000 400.0000 1837.8459 3 0 0 2 yes 5100.0000 400.0000 400.0000 4 0 0 0 yes 4800.0000 400.0000 1989.2250 5 0 0 3 yes 4800.0000 400.0000 1998.5601 6 0 0 3 yes 4800.0000 400.0000 1903.5920 7 0 0 4 yes 4800.0000 400.0000 1992.6300 8 0 0 4 yes 4800.0000 400.0000 1995.6570 9 0 0 5 yes 4800.0000 400.0000 2000.0000 10 0 0 5 yes 4800.0000 400.0000 400.0000 11 0 0 6 yes 3800.0000 400.0000 1851.2080 12 0 0 7 yes 3800.0000 400.0000 1160.6420 13 0 0 8 yes 3800.0000 400.0000 1776.4320 14 0 0 9 yes 3800.0000 400.0000 1557.6689 15 0 0 10 yes 3800.0000 400.0000 2000.6169 16 0 0 11 yes 3800.0000 400.0000 1427.8760 17 0 0 12 yes 3800.0000 400.0000 1960.1360 18 0 0 13 yes 3800.0000 400.0000 1628.4310 19 0 0 14 yes 2500.0000 400.0000 400.0000 20 0 0 15 yes 2500.0000 400.0000 400.0000 It seems that the system thinks my kernel is a kdump kernel, see dmesg: [ 0.089955] CPU topo: Boot CPU APIC ID not the first enumerated APIC ID: 20 > 10 [ 0.089956] CPU topo: Crash kernel detected. Disabling real BSP to prevent machine INIT I doubt that this is really the case, since I am working quite fine on it right now. Just missing one of my P-Core things. I have the newest official firmware, from lshw: incendara description: Notebook product: XPS 16 9640 (0C62) vendor: Dell Inc. serial: D0M3C24 width: 64 bits capabilities: smbios-3.6.0 dmi-3.6.0 smp vsyscall32 configuration: boot=normal chassis=notebook family=XPS sku=0C62 uuid=4c4c4544-0030-4d10-8033-c4c04f433234 *-core description: Motherboard product: 09CK4V vendor: Dell Inc. physical id: 0 version: A00 serial: /D0M3C24/CNWSC0044D113M/ *-firmware description: BIOS vendor: Dell Inc. physical id: 0 version: 1.3.0 date: 03/12/2024 size: 1MiB capacity: 64MiB capabilities: pci pnp upgrade shadowing cdboot bootselect edd int5printscreen int9keyboard int14serial int17printer acpi usb smartbattery biosbootspecification netboot uefi *-cpu description: CPU product: Intel(R) Core(TM) Ultra 9 185H vendor: Intel Corp. physical id: 400 bus info: cpu@0 version: 6.170.4 slot: U3E1 size: 1947MHz capacity: 4800MHz width: 64 bits clock: 100MHz capabilities: lm fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp x86-64 constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb ssbd ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rdseed adx smap clflushopt clwb intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves split_lock_detect user_shstk avx_vnni dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi vnmi umip pku ospke waitpkg gfni vaes vpclmulqdq tme rdpid bus_lock_detect movdiri movdir64b fsrm md_clear serialize pconfig arch_lbr ibt flush_l1d arch_capabilities intel_ppin cpufreq configuration: cores=16 enabledcores=16 microcode=28 threads=22
Created attachment 306294 [details] Full lshw.txt I added my full lshw.txt for further info
On Tue, May 14 2024 at 13:28, bugzilla-daemon@kernel.org wrote: > It seems that the system thinks my kernel is a kdump kernel, see dmesg: > > [ 0.089955] CPU topo: Boot CPU APIC ID not the first enumerated APIC ID: > 20 >> 10 > [ 0.089956] CPU topo: Crash kernel detected. Disabling real BSP to prevent > machine INIT > > I doubt that this is really the case, since I am working quite fine on it > right > now. Just missing one of my P-Core things. You can work on it obviously... Unfortunately the ACPI table does not conform to the specification: "To ensure that the boot processor is supported post initialization, two guidelines should be followed. The first is that OSPM should initialize processors in the order that they appear in the MADT. The second is that platform firmware should list the boot processor as the first processor entry in the MADT." "Failure of OSPM implementations and platform firmware to abide by these guidelines can result in both unpredictable and non optimal platform operation." The OS follows this guideline. The firmware not. Let me think about it some more. Thanks, tglx
I am happy to provide any additional information or dumps, if required, just let me know... (Still running the same "crash kernel" from yesterday, by the way, so the system itself is pretty stable).
Created attachment 306297 [details] Patch to address the problem of broken ACPI/MADT Can you please test the attached patch?
I just double checked with Windows and I found out that Windows 11 does see all 22 cores. I will try you patch later, once I figured out how to compile the kernel nowadays. My last kernel compile is at least 10 years ago, I just installed the mainline kernel from the ubuntu mainline ppa. Will take some time to come back with answers.
Hi Thomas, finally found the time for the kernel compile (busy day), but I can confirm that your patch solves my problem, e.g. "nproc" shows the expected number "22", and "lstopo" no longer misses half a P-Core with this kernel! Thanks so far!
I can't contribute much to the solution but I can confirm the error for MeteorLake i7Ultra 155H on Asrock NUCS-BOX 155H.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/x86/kernel/cpu/topology.c?id=9d22c96316ac59ed38e80920c698fed38717b91b Marked for stable so it should trickle out soon.