Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME (with Chinese translation comment)

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

From "H. Peter Anvin" <>

Date Fri, 20 Dec 2013 08:57:03 -0800

But we prefer the TAD for that.  The case where the EFI runtime is the only source of that info is problematic as they are known to not work at runtime.  We could collect it at boot and then never change it, although you end up in definitional issues between EFI and the hw RTC.

/* 但是那樣的狀況下我們比較喜歡 TAD. 在某種案例下 EFI runtime 是唯一的資訊來源但是它卻有問題, 因為我們已知它們在 runtime 無法運作. 我們可以在開機時收集它然後永遠不修改, 但是你最終會遭遇 EFI 和 hw RTC 間的定義上問題.  */

Matthew Garrett <matthew.garrett@nebula.com> wrote:
>On Thu, 2013-12-19 at 20:22 -0800, H. Peter Anvin wrote:
>> On 12/19/2013 08:05 PM, joeyli wrote:
>> > Can we use EFI time services on x86_64 after Borislav's patches
>accepted
>> > to mainline?

/* 當 Borislav 的 patches 被上游允許之後, 在x86_64是否我們可以使用 EFI time services? */

>> > 
>> 
>> No.

/* 不行. */

>
>We will want to use them to (at minimum) obtain the clock timezone.
>Using them for general RTC access is less attractive.

/* 我們想要(最低限度)使用他們以獲得時鐘時區. 用他們作為一般的RTC存取(功能)並沒有吸引力. */

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

From Matthew Garrett <>

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

Date Fri, 20 Dec 2013 16:58:33 +0000

On Fri, 2013-12-20 at 08:57 -0800, H. Peter Anvin wrote:
> But we prefer the TAD for that.  The case where the EFI runtime is the only source of that info is problematic as they are known to not work at runtime.  We could collect it at boot and then never change it, although you end up in definitional issues between EFI and the hw RTC.

Most shipping UEFI hardware has no TAD.

/* 大部份出貨的 UEFI 硬體沒有 TAD */

-- 
Matthew Garrett <matthew.garrett@nebula.com>

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

From "H. Peter Anvin" <>

Date Fri, 20 Dec 2013 12:29:51 -0800

Yes, but the TZ isn't all that critical, either.  It certainly doesn't matter at all for a pure Linux system.

/* 對, 但是 TZ 並不是那麼的關鍵. 在一個純 Linux 系統上它並不重要 */

Matthew Garrett <matthew.garrett@nebula.com> wrote:
>On Fri, 2013-12-20 at 08:57 -0800, H. Peter Anvin wrote:
>> But we prefer the TAD for that.  The case where the EFI runtime is
>the only source of that info is problematic as they are known to not
>work at runtime.  We could collect it at boot and then never change it,
>although you end up in definitional issues between EFI and the hw RTC.
>
>Most shipping UEFI hardware has no TAD.

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

From Matthew Garrett <>

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

Date Fri, 20 Dec 2013 20:32:12 +0000

On Fri, 2013-12-20 at 12:29 -0800, H. Peter Anvin wrote:
> Yes, but the TZ isn't all that critical, either.  It certainly doesn't matter at all for a pure Linux system.

No, but it does matter for a great number of deployed Linux systems.
Dealing with the timezone over DST changes has been a perpetual problem,
and if we can make that work then life will be significantly better.

/* 不, 但它對於一個已大量佈署的 Linux 系統很重要. 處理在時區上的DST變化是個永遠的課題, 如果我們可以讓它運作, 那麼生活會更加美好 */

-- 
Matthew Garrett <matthew.garrett@nebula.com>

Date Fri, 20 Dec 2013 13:14:25 -0800

From "H. Peter Anvin" <>

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

On 12/20/2013 12:32 PM, Matthew Garrett wrote:
> On Fri, 2013-12-20 at 12:29 -0800, H. Peter Anvin wrote:
>> Yes, but the TZ isn't all that critical, either.  It certainly doesn't matter at all for a pure Linux system.
> 
> No, but it does matter for a great number of deployed Linux systems.
> Dealing with the timezone over DST changes has been a perpetual problem,
> and if we can make that work then life will be significantly better.
> 

And as I pointed out, it can matter a lot for VMs, since the provider
doesn't want to provision the VMs differently for different types of guests.

/* 就像我指出的, 它對虛擬機更重要, 因為供應商不希望對於不同型態的 guest 提供有差別的虛擬機 */

 -hpa

Date Fri, 20 Dec 2013 13:12:52 -0800

From "H. Peter Anvin" <>

Subject Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME

On 12/20/2013 07:16 AM, Matthew Garrett wrote:
> On Thu, 2013-12-19 at 20:22 -0800, H. Peter Anvin wrote:
>> On 12/19/2013 08:05 PM, joeyli wrote:
>>> Can we use EFI time services on x86_64 after Borislav's patches accepted
>>> to mainline?
>>>
>>
>> No.
> 
> We will want to use them to (at minimum) obtain the clock timezone.
> Using them for general RTC access is less attractive.
> 

One option is to use the EFI runtime call to get and save the clock
timezone before we call ExitBootServices() in the EFI stub.  This
doesn't obviate the need for proper handling of the TAD, though,
especially since it is likely that future hardware will not have a RTC
in the current form (it is a way more complex device than is needed,
which wouldn't normally be a problem, but the fact that it has to
operate in the Vbat well makes it a major one.)

/* 有個選項是我們可以在 EFI stub 內, 調用 ExitBootServices() 之前, 使用 EFI runtime call 取得和儲存時鐘時區. 雖然這樣仍無法避免需妥善處理 TAD, 特別是因為未來的硬體很可能沒有現在這種形式的 RTC (它是一種比需求更複雜的設備, 這通常不會是個問題, 但事實上, 它必須具備在Vbat(電池)下運作良好的重大特性) */

 -hpa