Messages in this thread | | | Date | Fri, 28 Dec 2012 12:40:56 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 1/3] rtc-efi: register rtc-efi device when EFI enabled |
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On 12/28/2012 11:17 AM, Matthew Garrett wrote: > On Fri, 2012-12-28 at 11:07 -0800, H. Peter Anvin wrote: >> We do have such machines, which is why this change has been reverted twice already. I believe we should stick to the priority scheme I proposed a few weeks ago. > > I seem to have missed that discussion, and couldn't find it after a > brief search. Got a pointer? >
Looks like it was a non-public distribution ... anyway, what I wrote was:
> I suspect that what we *should* do looks like: > > 1. If ACPI exports a Time and Alarm Device (ACPI000E) the use it; > 2. If ACPI exports an PC/AT device (PNP0B00/1/2) then use it(*); > 3. If we have an EFI RTC use it; > 4. Probe for a PC/AT RTC device. > > I'm unsure what the ordering of 1 & 2 should be. The ACPI device has > the advantage that it contains time zone information, which is important > for Windows interoperability, and at least optionally supports > millisecond resolution; there is no way to even export "this is where > you find time zone information" (since we're dealing with an RTC with > embedded CMOS, there is storage available, it is just a matter of > telling the OS how to find it) for the PNP0B0x devices. > > The TAD is also guaranteed to map 1:1 to the EFI RTC. > > -hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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