On Fri, 22 Sep 2017 10:04:53 +0200, Johannes Stezenbach wrote: > > On Fri, Sep 22, 2017 at 12:35:15AM +0200, Rafael J. Wysocki wrote: > > On Thursday, September 21, 2017 6:23:07 PM CEST Johannes Stezenbach wrote: > > > On Thu, Sep 21, 2017 at 04:21:46PM +0200, Rafael J. Wysocki wrote: > > > > So I would be inclined to think of that as a BIOS issue. > > > > > > OK, wrt $Subject it sparks the question how to fix the > > > issue exposed by commit d31fd43c0f9a4 "clk: x86: Do not > > > gate clocks enabled by the firmware". Add quirks to > > > the drivers for the devices that have the dangling > > > PowerResources and manually call _OFF/_ON during suspend/resume? > > > > > > I must admit I haven't looked deeper into the issue yet, > > > i.e. I don't know which clock causes S0ix failure. > > > If I understand correctly, before d31fd43c0f9a4 the > > > clk framework would just disable all unused clocks > > > registered by clk-pmc-atom.c, which are all of then except > > > CLK3 which is used by the audio codec. And the audio codec > > > would disable CLK3 during suspend. > > > After d31fd43c0f9a4 all clocks that BIOS had enabled during boot > > > are kept running. Presumably we could also add the quirk to > > > clk-pmc-atom.c to bypass what d31fd43c0f9a4 added on Asus E200HA? > > > > Since this is S0ix, the "system level" is 0 all the time (as I said in a > > previous message). > > Damn. Reading ACPI spec (6.1 and 6.2), it talks about _LPI and _RDI > but E200HA doesn't have that in any ACPI table. > The table in section 7.1 Power Resource Objects and the Power Management Models > says "Choose a supported device state to enable a targeted system sleep or > Low- power Idle state ... [use] _PRx". > > > So there seem to be two possible ways to address this, unfortunately both > > based on white- or blacklisting. > > > > One of them would be to only do the d31fd43c0f9a4 approach for selected > > systems where it needs to be done to avoid breakage. The other one would > > be to do it for all systems by default and blacklist the ones where that > > leads to problems. > > > > IMO it is better to disable clocks over suspend-resume, because that reduces > > the system's power draw while suspended. So that's what I would do and then > > keep the clocks running only if that is known to be necessary. > > d31fd43c0f9a4 was added to fix a "hard hangup on boot" issue, > so I guess the default should be to keep clocks enabled. > > BTW, in E200HA DSDT, the PowerResources in question are children of > the I2Cx devices, presumably it means these clocks are to be used by > devices connected to the i2c busses. Maybe it's a left over from devices > that are not present in E200HA, and we should ignore them. > > In conclusion the BIOS bug is that it enables these clocks at boot, > and the correct quirk is to make clk-pmc-atom.c disable them during init, > but leave the _PRx handling for the used clocks (CLK3) to ACPI. Well, I can't say which is the buggy behavior, but at least, I agree with Rafael that white/blacklisting is likely the way to go. One thing I'm wondering is whether it's specific to device or specific to platform. The ASUS one that showed a regression Johannes and I have is the Cherrytrail, while the device showed the hang-at-boot was Baytrail, IIRC. thanks, Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
