Hi, Rafael > From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx] > Sent: Tuesday, May 13, 2014 9:31 AM > To: Zheng, Lv > Cc: RobertBMoore@xxxxxxxxxxxxxx; Thomas Renninger (trenn@xxxxxxx); Oswald Buddenhagen; ACPI Devel Maling List; Linux > Kernel Mailing List > Subject: Re: [PATCH] ACPICA: Revert "ACPICA: Add option to favor 32-bit FADT addresses." > > On Tuesday, May 13, 2014 01:05:59 AM Zheng, Lv wrote: > > Hi, > > > > > From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx] > > > Sent: Tuesday, May 13, 2014 8:09 AM > > > > > > On Monday, May 12, 2014 08:51:36 AM Zheng, Lv wrote: > > > > Hi, Rafael > > > > > > > > I checked the bug. > > > > > > > > The dmesg of the kernel without the bisected commit: > > > > [ 0.000000] ACPI BIOS Warning (bug): Incorrect checksum in table [XSDT] - 0xA0, should be 0xC9 (20140214/tbprint-218) > > > > [ 0.000000] ACPI Warning: 32/64 FACS address mismatch in FADT - two FACS tables! (20140214/tbfadt-395) > > > > [ 0.000000] ACPI BIOS Warning (bug): 32/64X FACS address mismatch in FADT - 0xCF661F40/0x00000000CF667E40, using 32 > > > (20140214/tbfadt-522) > > > > > > > > The dmesg of the kernel with the bisected commit: > > > > [ 0.000000] ACPI BIOS Warning (bug): Incorrect checksum in table [XSDT] - 0xA0, should be 0xC9 (20131218/tbprint-214) > > > > [ 0.000000] ACPI BIOS Warning (bug): 32/64X FACS address mismatch in FADT: 0xCF661F40/0x00000000CF667E40, using 64-bit > > > address (20131218/tbfadt-271) > > > > > > > > This is the purpose of the bisected commit. > > > > According to the link below: > > > > http://bugs.acpica.org/show_bug.cgi?id=885 > > > > And Windows documentation: > > > > http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/CPA002_WH06.ppt > > > > We believe 64-bit addresses should be used by default so that new features can be enabled according to the public knowledge > of > > > Windows Vista+ behavior. > > > > For old Windows, it's hard for us to guess, we should wait for the reports and add quirks for them. > > > > > > > > Thus this commit is not wrong, it shouldn't be reverted. > > > > > > It is wrong, because it breaks a system that worked without it. > > > > > > It's *that* simple. > > > > For this commit, we knew there would be systems broken. > > And was prepared to add quirks for them. > > The quirks are not there just because we rely on end users to report. > > > > > > > > And either you have a fix for that (which is not a quirk, because there may be > > > more machines like that), or we have to revert it. > > > > > > > Though this platform is newer than vista, we still should offer a quirk mechanism > > > > for it as a quick fix: > > > > > > We didn't need a quirk for it before, though. > > > > But according to BZ885, we need more quirks for other machines before. > > For example, ThinkPad 40e and ThinkPad 51e reported in the BZ885. > > > > > > > > So really, I'm reverting it. > > > > OK. > > I'll first try to figure out the cause of the issue that is happening to Intel DP45SG. > > And then try this approach again in a smarter way that is more tolerant torward the possible regressions. > > Great, thanks! If you have troubles in reverting things. I can offer one line patch to revert the functionality of the bisected commit back to the original behavior. In acpixf.h, make acpi_gbl_use32_bit_fadt_address to TRUE can be a fix. I'll ask for the test on the bugzilla. Thanks and best regards -Lv > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
