Date: Thu, 12 Jul 2007 18:55:15 -0700 From: Nate Lawson <nate@root.org> To: current@FreeBSD.org Subject: patch to catch non-working hpet Message-ID: <4696DB83.4000803@root.org>
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I need someone to test this code. You have to have an HPET timer. It
should detect the case where it's non-working on at least one Acer
system but not break others. Your system should boot and work normally
with no change in dmesg. Let me know if it breaks something, thx.
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Index: sys/dev/acpica/acpi_hpet.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/acpica/acpi_hpet.c,v
retrieving revision 1.5.2.4
diff -u -r1.5.2.4 acpi_hpet.c
--- sys/dev/acpica/acpi_hpet.c 18 Jun 2007 00:29:55 -0000 1.5.2.4
+++ sys/dev/acpica/acpi_hpet.c 12 Jul 2007 21:20:27 -0000
@@ -144,7 +144,7 @@
{
struct acpi_hpet_softc *sc;
int rid;
- uint32_t val;
+ uint32_t val, val2;
uintmax_t freq;
ACPI_FUNCTION_TRACE((char *)(uintptr_t) __func__);
@@ -167,6 +167,9 @@
return (ENXIO);
}
+ /* Be sure timer is enabled. */
+ bus_write_4(sc->mem_res, HPET_OFFSET_ENABLE, 1);
+
/* Read basic statistics about the timer. */
val = bus_read_4(sc->mem_res, HPET_OFFSET_PERIOD);
freq = (1000000000000000LL + val / 2) / val;
@@ -179,12 +182,23 @@
((val >> 13) & 1) ? " count_size" : "");
}
- /* Be sure it is enabled. */
- bus_write_4(sc->mem_res, HPET_OFFSET_ENABLE, 1);
-
if (testenv("debug.acpi.hpet_test"))
acpi_hpet_test(sc);
+ /*
+ * Don't attach if the timer never increments. Since the spec
+ * requires it to be at least 10 MHz, it has to change in 1 us.
+ */
+ val = bus_read_4(sc->mem_res, HPET_OFFSET_VALUE);
+ DELAY(1);
+ val2 = bus_read_4(sc->mem_res, HPET_OFFSET_VALUE);
+ if (val == val2) {
+ device_printf(dev, "HPET never increments, disabling\n");
+ bus_write_4(sc->mem_res, HPET_OFFSET_ENABLE, 0);
+ bus_free_resource(dev, SYS_RES_MEMORY, sc->mem_res);
+ return (ENXIO);
+ }
+
hpet_timecounter.tc_frequency = freq;
hpet_timecounter.tc_priv = sc;
tc_init(&hpet_timecounter);
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