Messages in this thread Patch in this message | | | Date | Mon, 21 Oct 2013 09:31:57 +0100 | From | "Jan Beulich" <> | Subject | [PATCH v2] x86: honor ACPI FADT flag indicating absence of a CMOS RTC |
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Even though the omission was found only during code review (originally in the Xen hypervisor, looking through ACPI v5 flags and their meanings and uses), we shouldn't be creating a corresponding platform device in that case.
Signed-off-by: Jan Beulich <jbeulich@suse.com> --- v2: Emit a log message in this case, as requested by Ingo. --- arch/x86/kernel/rtc.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- 3.12-rc6/arch/x86/kernel/rtc.c +++ 3.12-rc6-x86-ACPI-no-RTC/arch/x86/kernel/rtc.c @@ -192,6 +192,14 @@ static __init int add_rtc_cmos(void) if (mrst_identify_cpu()) return -ENODEV; +#ifdef CONFIG_ACPI + if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) { + /* This warning can likely go away again in a year or two. */ + pr_info("ACPI: not registering RTC platform device\n"); + return -ENODEV; + } +#endif + platform_device_register(&rtc_device); dev_info(&rtc_device.dev, "registered platform RTC device (no PNP device found)\n");
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