On Tue, Jul 14, 2020 at 4:11 PM Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: > > On 2020-07-14 15:54:57 [+0200], Rafael J. Wysocki wrote: > > On Tue, Jul 14, 2020 at 3:44 PM Sebastian Andrzej Siewior > > <bigeasy@xxxxxxxxxxxxx> wrote:> > > > On 2020-06-24 23:49:52 [+0200], Stephen Berman wrote: > > > > > > Let me summarize the thread here: > > > > > > On Stephen's system, ACPI informs the thermal zone driver to poll the > > > temperature every second and the driver does so. > > > The driver queries the temperature by invoking acpi_evaluate_integer() > > > which invokes (at some point) acpi_ev_queue_notify_request(). > > > > Well, I don't quite see how acpi_ev_queue_notify_request() can be > > invoked from the acpi_evaluate_integer() code path. > > > > Do you have a call trace showing that? > > So the trace in > https://lore.kernel.org/linux-acpi/87o8pjh1i0.fsf@xxxxxxx/ > > shows the pattern and we nailed it down that it comes from > thermal_get_temp(). acpi_evaluate_integer() doesn't show up in the trace, though, AFAICS. > I assumed acpi_ex_opcode_2A_0T_0R() since the other > candidate was acpi_ev_asynch_execute_gpe_method(). Which probably is the case. Specifically acpi_ev_asynch_execute_gpe_method: Evaluate _L66 is likely to cause the Notify() to be dispatched. > Stephen, the patch attached adds a WARN_ON() statement which will > produce a stack trace (4 or so). Could please run 'dmesg' after a while > and send it back. There should be a > "WARNING in drivers/acpi/acpica/evmisc.c" > > statement or something along the lines. > > Rafael, are you also interested in an ACPI dump? That might help a bit. So what probably happens is that poking at the TZ causes a GPE to trigger and a Notify() to be dispatched which then goes into the workqueue for execution. Now, I'm not sure what happens to those Notify() items, though. They each should cause a handler (in the thermal driver) to be executed, but does that happen?
