mb/emulation/qemu-q35: don't select CONFIG_UNKNOWN_TSC_RATE#903
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mb/emulation/qemu-q35: don't select CONFIG_UNKNOWN_TSC_RATE#903SergiiDmytruk wants to merge 1 commit into
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This option signifies missing implementation of tsc_freq_mhz() which results in tsc_freq_mhz() from src/arch/x86/timestamp.c returning zero. That zero in turn gets put into TIMESTAMP CBMEM table requiring payloads and user-space tools to figure the frequency on their own. Implement tsc_freq_mhz() to query timer frequency in coreboot, so it gets reported downstream. Change-Id: I88d1206c13f15a9f20c07b65dcec42ec614f7e6a Upstream-Status: Pending Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
miczyg1
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May 25, 2026
| /* Mimics implementation of acpi_fill_fadt() in southbridge/intel/i82801ix/fadt.c. */ | ||
| u16 pmbase = pci_read_config16(PCI_DEV(0, 0x1f, 0), 0x40) & 0xfffe; | ||
| u16 pm_tmr_blk = pmbase + PM1_TMR; | ||
| return inl(pm_tmr_blk); |
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@SergiiDmytruk this returns the current tick, not the frequency. Am I right?
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Oh, right, not sure how I confused it for frequency which is actually hard-coded (as used by AcpiTimerLib selected for QEMU). Should it be simply returned here or better to make EDK handle 0 in some sensible way?
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This option signifies missing implementation of
tsc_freq_mhz()which results intsc_freq_mhz()fromsrc/arch/x86/timestamp.creturning zero. That zero in turn gets put into TIMESTAMP CBMEM table requiring payloads and user-space tools to figure the frequency on their own.Dasharo/edk2@0beada2 fixed parsing of TIMESTAMP table, resulting in division by zero when starting QEMU. Addressing it in coreboot, similarly to the fix for APUs in #887. This fixes CI failures like https://github.com/Dasharo/coreboot/actions/runs/26337084146/job/77532919152#step:11:13.