Hi, Rafael > From: rjwysocki@xxxxxxxxx [mailto:rjwysocki@xxxxxxxxx] On Behalf Of > Rafael J. Wysocki > Subject: Re: acpi: broken suspend to RAM with v4.7-rc1 > > On Mon, Jun 13, 2016 at 12:07 PM, Andrey Skvortsov > <andrej.skvortzov@xxxxxxxxx> wrote: > > Hi Lv, > > > > On 13 Jun, Zheng, Lv wrote: > >> > From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi- > >> > owner@xxxxxxxxxxxxxxx] On Behalf Of Rafael J. Wysocki > >> > Subject: Re: acpi: broken suspend to RAM with v4.7-rc1 > >> > > >> > On Saturday, June 11, 2016 01:49:22 PM Andrey Skvortsov wrote: > >> > > On 10 Jun, Rafael J. Wysocki wrote: > >> > > > On Friday, June 10, 2016 11:32:10 PM Andrey Skvortsov wrote: > >> > > > > Hi, > >> > > > > > >> > > > > On my laptop (DELL Vostro 1500) in v4.7-rc1 is broken suspend > to RAM. > >> > > > > Laptop doesn't finish suspend to RAM process (disks are off, but > >> > > > > WiFi and Power LEDs are still on). The only way to get it out of > >> > > > > this state, is to turn the power off. > >> > > > > > >> > > > > I've bisected the issue to commit 66b1ed5aa8dd25 > >> > > > > [ACPICA: ACPI 2.0, Hardware: Add access_width/bit_offset > support > >> > > > > for acpi_hw_write()]. > >> > > > > > >> > > > > If I revert this commit in v4.7-rc1 (or v4.7-rc2), suspend to RAM > >> > > > > is working again. > >> > > > > > >> > > > > The cause of this problem is that after this commit write to > PM1A > >> > > > > Control Block (16-bit register) is done using two 8-bit writes. > >> > > > > If I force this write to be 16-bit, then all is working as before. > >> > > > > > >> > > > > To get it working 'access_width' for PM1A Control Block needs > to > >> > > > > be 2 (16-bit), but it's 1 (8-bit). > >> [Lv Zheng] > >> Could you send me the acpidump of the machine? > > Here it is > > > https://dl.dropboxusercontent.com/u/24023626/dell_vostro_1500.acpid > ump.bin > > > >> > > > > > >> > > > > The root of the problem seems to be not the commit > >> > 66b1ed5aa8dd25 > >> > > > > itself, but the ACPI tables in BIOS where wrong access_width > >> > > > > comes from. I fixed problem in FACP table, put it in initrd to > >> > > > > override FACP table from BIOS. This fixed the issue, suspend to > >> > > > > RAM is working now again. > >> > > > > > >> > > > > But I'm not sure whether is this proper fix for this problem. > >> > > > > Is there any place in the kernel, where such ACPI quirks are > placed? > >> [Lv Zheng] > >> My question would be: > >> Does Windows behave correctly for this table? > > Yes, suspend to RAM is working under Windows Vista. > > IIRC it worked under Windows XP too. > > > >> However there is a real case showing that there are real tables need us > to correctly support BitWidth/BitOffset. > >> Here is the information for you to refer: > >> http://permalink.gmane.org/gmane.linux.kernel.commits.head/313870 > >> > >> > > > > >> > > > Well, if the commit in question caused a problem to happen for > you, > >> > > > it also might cause similar problems to happen elsewhere. > >> > > > > >> > > > It looks like we'll need to revert that commit. > >> > > Hi, > >> > > > >> > > or maybe to reset access_width AnyAcc from FACP table only for > PM1A > >> > > control register or even for all registers? This will fix the issue too. > >> > > >> > That's a good idea actually. > >> > > >> > > diff --git a/drivers/acpi/acpica/tbfadt.c > >> > > b/drivers/acpi/acpica/tbfadt.c index 6208069..a476e94 100644 > >> > > --- a/drivers/acpi/acpica/tbfadt.c > >> > > +++ b/drivers/acpi/acpica/tbfadt.c > >> > > @@ -714,7 +714,14 @@ static void > acpi_tb_setup_fadt_registers(void) > >> > > } > >> > > } > >> > > } > >> > > > >> > > + /* > >> > > + * Reset access_width in the GAS for PM1A control register to > >> > > + * undefined value. Because in some cases this field contains > >> > > + * wrong value. > >> > > + */ > >> > > + acpi_gbl_FADT.xpm1a_control_block.access_width = 0; > >> > > >> > OK, let's see what Bob and Lv think about that. > >> [Lv Zheng] > >> There is a commit in 4.7-rc2: > >> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id= > 7f9bef9d > >> Have you tried if the problem still exists in 4.7-rc2? > > I've just tried v4.7-rc3. It contains commit 7f9bef9d and the problem > > exists there too. > > I have decided to revert commit 66b1ed5aa8dd25 as in principle other > registers may be similarly affected on other systems. [Lv Zheng] Yes. I didn't prepare fallback mechanism for this support. It seems we have to do the reversion. Please revert it. Next time I'll prepare a quirk mechanism when this is upstreamed. For Andrey: Could you provide me the DMIdecode output of the machine? Thanks -Lv > > Thanks, > Rafael ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
