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Remove cpu_deepest_sleep variable.

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On Core2 and older Intel CPUs, where TSC stops in C2, system does not
allow C2 entrance if timecounter hardware is TSC.  This is done by
tc_windup() which tests for TC_FLAGS_C2STOP flag of the new
timecounter and increases cpu_disable_c2_sleep if flag is set.  Right
now init_TSC_tc() only sets the flag if cpu_deepest_sleep >= 2, but
TSC is initialized too early for this variable to be set by
acpi_cpu.c.

There is no reason to require that ACPI reported C2 and deeper states
to set TC_FLAGS_C2STOP, so remove cpu_deepest_sleep test from
init_TSC_tc() condition.  And since this is the only use of the
variable, remove it at all.

Reported and submitted by:	Jia-Shiun Li <jiashiun@gmail.com>
Suggested by:	jhb
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2017-02-24 16:11:55 +00:00
parent 9c8efa1dfb
commit 8cd5962571
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=314211
4 changed files with 2 additions and 11 deletions
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9
sys/dev/acpica/acpi_cpu.c
View File

@ -703,7 +703,6 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
sc->cpu_non_c2 = sc->cpu_cx_count;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
cpu_deepest_sleep = 1;
/*
* The spec says P_BLK must be 6 bytes long. However, some systems
@ -729,7 +728,6 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
cx_ptr++;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
cpu_deepest_sleep = 2;
}
}
if (sc->cpu_p_blk_len < 6)
@ -746,7 +744,6 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
cx_ptr++;
sc->cpu_cx_count++;
cpu_deepest_sleep = 3;
}
}
}
@ -831,7 +828,6 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
cx_ptr->type = ACPI_STATE_C0;
cx_ptr++;
sc->cpu_cx_count++;
cpu_deepest_sleep = 1;
/* Set up all valid states. */
for (i = 0; i < count; i++) {
@ -884,8 +880,6 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
continue;
case ACPI_STATE_C2:
sc->cpu_non_c3 = sc->cpu_cx_count;
if (cpu_deepest_sleep < 2)
cpu_deepest_sleep = 2;
break;
case ACPI_STATE_C3:
default:
@ -894,8 +888,7 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
"acpi_cpu%d: C3[%d] not available.\n",
device_get_unit(sc->cpu_dev), i));
continue;
} else
cpu_deepest_sleep = 3;
}
break;
}

1
sys/kern/kern_clocksource.c
View File

@ -54,7 +54,6 @@ __FBSDID("$FreeBSD$");
#include <machine/cpu.h>
#include <machine/smp.h>
int cpu_deepest_sleep = 0; /* Deepest Cx state available. */
int cpu_disable_c2_sleep = 0; /* Timer dies in C2. */
int cpu_disable_c3_sleep = 0; /* Timer dies in C3. */

1
sys/sys/systm.h
View File

@ -321,7 +321,6 @@ sbintime_t cpu_idleclock(void);
void cpu_activeclock(void);
void cpu_new_callout(int cpu, sbintime_t bt, sbintime_t bt_opt);
void cpu_et_frequency(struct eventtimer *et, uint64_t newfreq);
extern int cpu_deepest_sleep;
extern int cpu_disable_c2_sleep;
extern int cpu_disable_c3_sleep;

2
sys/x86/x86/tsc.c
View File

@ -542,7 +542,7 @@ init_TSC_tc(void)
* result incorrect runtimes for kernel idle threads (but not
* for any non-idle threads).
*/
if (cpu_deepest_sleep >= 2 && cpu_vendor_id == CPU_VENDOR_INTEL &&
if (cpu_vendor_id == CPU_VENDOR_INTEL &&
(amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
tsc_timecounter.tc_flags |= TC_FLAGS_C2STOP;
if (bootverbose)