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_h= > > > w_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 B= > > > lock > > > (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-b= > > > it), but it's=20 > > > 1 (8-bit). > > > > > > The root of the problem seems to be not the commit 66b1ed5aa8dd25 itself, b= > > > ut 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? > > > > 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.
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