Messages in this thread | | | Subject | RE: x86-64 with nvidia MCP51 chipset: kernel does not find HPET | From | Lee Revell <> | Date | Mon, 30 Oct 2006 14:00:44 -0500 |
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On Mon, 2006-10-30 at 11:07 -0600, Langsdorf, Mark wrote: > > I have a 6 month old x86-64 machine with nvidia MCP51 chipset on which > > the kernel does not detect the HPET. According to HPET maintainer > > Clemens Ladisch, this machine certainly has one, but it cannot be > > enabled for lack of hardware documentation. > > > > Is there anything I can do to help debug this? > > If the hardware is not providing the HPET description in ACPI, > there's little you can do, and most vendors do not provide > the HPET description. > > Do you know if there's an entry for HPET in the ACPI?
I'm not exactly an ACPI expert, but I do not think there is an entry for HPET in the ACPI, as the check in arch/x86_64/kernel/io_apic.c fails:
358 /* 359 * All timer overrides on Nvidia are 360 * wrong unless HPET is enabled. 361 */ 362 nvidia_hpet_detected = 0; 363 acpi_table_parse(ACPI_HPET, 364 nvidia_hpet_check); 365 if (nvidia_hpet_detected == 0) { 366 acpi_skip_timer_override = 1; 367 printk(KERN_INFO "Nvidia board " 368 "detected. Ignoring ACPI " 369 "timer override.\n"); 370 }
But, with some help from anonymous sources, I have been able to find the HPET and make it work using a userspace driver that pokes registers by mmap'ing /dev/mem. So we just need a way to tell the kernel it's there. Presumably this would require a PCI quirk.
Is this likely to be worth the trouble?
Lee
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