From mboxrd@z Thu Jan 1 00:00:00 1970 From: joeyli Subject: Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME Date: Sat, 21 Dec 2013 10:43:25 +0800 Message-ID: <1387593805.3539.4983.camel@linux-s257.site> References: <1387439053-8711-1-git-send-email-jlee@suse.com> <1387517916.3539.4446.camel@linux-s257.site> <52B4B242.5010002@zytor.com> <2787644.ytU7M33B4r@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <2787644.ytU7M33B4r-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Rafael J. Wysocki" Cc: "H. Peter Anvin" , Alessandro Zummo , Matt Fleming , Matthew Garrett , Elliott-VXdhtT5mjnY@public.gmane.org, samer.el-haj-mahmoud-VXdhtT5mjnY@public.gmane.org, Oliver Neukum , werner-IBi9RG/b67k@public.gmane.org, trenn-l3A5Bk7waGM@public.gmane.org, JBeulich-IBi9RG/b67k@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Borislav Petkov List-Id: linux-efi@vger.kernel.org =E6=96=BC =E4=BA=94=EF=BC=8C2013-12-20 =E6=96=BC 22:45 +0100=EF=BC=8CRa= fael J. Wysocki =E6=8F=90=E5=88=B0=EF=BC=9A > On Friday, December 20, 2013 01:10:26 PM H. Peter Anvin wrote: > > On 12/19/2013 09:38 PM, joeyli wrote: > > >=20 > > > If don't use EFI time, then the first priority is using ACPI TAD = if it > > > present. Due to ACPI TAD is a generic acpi device that's need OS = parsing > > > DSDT table before set system time. > > >=20 > > > Either move DSDT parser from subsystem initial stage to start_ker= nel or > > > move timekeeping initial to after DSDT be parsed. Which one you t= hink is > > > more possible and risk less? Then I will try that way. > > >=20 > >=20 > > I discussed the DSDT/SSDT parsing issue with Rafael and he claims i= t > > would require a lot of restructuring. Unfortunately ACPI is at thi= s > > point done rather late, as I understand. All of this is a big prob= lem. >=20 > My understanding, however, is that to use the TAD, we don't actually = need to > create a struct acpi_device for it. We just need a handle to the ACP= ICA > object which can be found using acpi_get_devices() as soon as the nam= espace > has been extracted from the DSDT and friends. That in turn happens i= n > acpi_early_init(), which is called from start_kernel() right before > efi_late_init(). >=20 > Is that early enough? >=20 > Rafael >=20 Thanks for your good suggestion, then I have a direction on using ACPI TAD earlier. Joey Lee