On Fri, Aug 9, 2019 at 2:00 PM Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > Hi Rafael, > > On 2019-08-02 12:45, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > According to Section 3.5 of the "Intel Low Power S0 Idle" document [1], > > Function 5 of the LPS0 _DSM is expected to be invoked when the system > > configuration matches the criteria for entering the target low-power > > state of the platform. In particular, this means that all devices > > should be suspended and in low-power states already when that function > > is invoked. > > > > This is not the case currently, however, because Function 5 of the > > LPS0 _DSM is invoked by it before the "noirq" phase of device suspend, > > which means that some devices may not have been put into low-power > > states yet at that point. That is a consequence of the previous > > design of the suspend-to-idle flow that allowed the "noirq" phase of > > device suspend and the "noirq" phase of device resume to be carried > > out for multiple times while "suspended" (if any spurious wakeup > > events were detected) and the point of the LPS0 _DSM Function 5 > > invocation was chosen so as to call it (and LPS0 _DSM Function 6 > > analogously) once per suspend-resume cycle (regardless of how many > > times the "noirq" phases of device suspend and resume were carried > > out while "suspended"). > > > > Now that the suspend-to-idle flow has been redesigned to carry out > > the "noirq" phases of device suspend and resume once in each cycle, > > the code can be reordered to follow the specification that it is > > based on more closely. > > > > For this purpose, add ->prepare_late and ->restore_early platform > > callbacks for suspend-to-idle, to be executed, respectively, after > > the "noirq" phase of suspending devices and before the "noirq" > > phase of resuming them and make ACPI use them for the invocation > > of LPS0 _DSM functions as appropriate. > > > > While at it, move the LPS0 entry requirements check to be made > > before invoking Functions 3 and 5 of the LPS0 _DSM (also once > > per cycle) as follows from the specification [1]. > > > > Link: https://uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf # [1] > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > --- > > > > In v2 this was patch 2. > > > > --- > > drivers/acpi/sleep.c | 36 ++++++++++++++++++++++++------------ > > include/linux/suspend.h | 2 ++ > > kernel/power/suspend.c | 12 +++++++++--- > > 3 files changed, 35 insertions(+), 15 deletions(-) > > > > Index: linux-pm/drivers/acpi/sleep.c > > =================================================================== > > --- linux-pm.orig/drivers/acpi/sleep.c > > +++ linux-pm/drivers/acpi/sleep.c > > @@ -954,11 +954,6 @@ static int acpi_s2idle_begin(void) > > > > static int acpi_s2idle_prepare(void) > > { > > - if (lps0_device_handle && !sleep_no_lps0) { > > - acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF); > > - acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY); > > - } > > - > > if (acpi_sci_irq_valid()) > > enable_irq_wake(acpi_sci_irq); > > > > @@ -972,11 +967,22 @@ static int acpi_s2idle_prepare(void) > > return 0; > > } > > > > -static void acpi_s2idle_wake(void) > > +static int acpi_s2idle_prepare_late(void) > > { > > - if (lps0_device_handle && !sleep_no_lps0 && pm_debug_messages_on) > > + if (!lps0_device_handle || sleep_no_lps0) > > + return 0; > > + > > + if (pm_debug_messages_on) > > lpi_check_constraints(); > > > > + acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF); > > + acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY); > > + > > + return 0; > > +} > > + > > +static void acpi_s2idle_wake(void) > > +{ > > /* > > * If IRQD_WAKEUP_ARMED is set for the SCI at this point, the SCI has > > * not triggered while suspended, so bail out. > > @@ -1011,6 +1017,15 @@ static void acpi_s2idle_wake(void) > > rearm_wake_irq(acpi_sci_irq); > > } > > > > +static void acpi_s2idle_restore_early(void) > > +{ > > + if (!lps0_device_handle || sleep_no_lps0) > > + return; > > + > > + acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT); > > + acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON); > > +} > > + > > static void acpi_s2idle_restore(void) > > { > > s2idle_wakeup = false; > > @@ -1021,11 +1036,6 @@ static void acpi_s2idle_restore(void) > > > > if (acpi_sci_irq_valid()) > > disable_irq_wake(acpi_sci_irq); > > - > > - if (lps0_device_handle && !sleep_no_lps0) { > > - acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT); > > - acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON); > > - } > > } > > > > static void acpi_s2idle_end(void) > > @@ -1036,7 +1046,9 @@ static void acpi_s2idle_end(void) > > static const struct platform_s2idle_ops acpi_s2idle_ops = { > > .begin = acpi_s2idle_begin, > > .prepare = acpi_s2idle_prepare, > > + .prepare_late = acpi_s2idle_prepare_late, > > .wake = acpi_s2idle_wake, > > + .restore_early = acpi_s2idle_restore_early, > > .restore = acpi_s2idle_restore, > > .end = acpi_s2idle_end, > > }; > > Index: linux-pm/kernel/power/suspend.c > > =================================================================== > > --- linux-pm.orig/kernel/power/suspend.c > > +++ linux-pm/kernel/power/suspend.c > > @@ -253,13 +253,19 @@ static int platform_suspend_prepare_late > > > > static int platform_suspend_prepare_noirq(suspend_state_t state) > > { > > - return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ? > > - suspend_ops->prepare_late() : 0; > > + if (state == PM_SUSPEND_TO_IDLE) { > > + if (s2idle_ops && s2idle_ops->prepare_late) > > + return s2idle_ops->prepare_late(); This should be return s2idle_ops && s2idle_ops->prepare_late ? s2idle_ops->prepare_late() : 0; > > + } > > + return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0; > > This unconditionally references suspend_ops here, what wasn't done > earlier. On one of my test boards (OdroidXU) it causes following NULL > pointer dereference since Linux next-20190809 (the first -next, which > contains this patch): Sorry about this, will fix early next week.
