On Thu, Sep 08, 2022 at 08:31:21PM -0500, Scott Cheloha wrote: > On Sat, Aug 27, 2022 at 09:28:06PM -0500, Scott Cheloha wrote: > > Whoops, forgot about the split read problem. My mistake. > > > > Because 32-bit platforms cannot do bus_space_read_8 atomically, and > > i386 can use acpihpet(4), we can only safely use the lower 32 bits of > > the counter in acpihpet_delay() (unless we want two versions of > > acpihpet_delay()... which I don't). > > > > Switch from acpihpet_r() to bus_space_read_4(9) and accumulate cycles > > as we do in acpihpet_delay(). Unlike acpitimer(4), the HPET is a > > 64-bit counter so we don't need to mask the difference between val1 > > and val2. > > > > [...] > > 12 day ping. > > This needs fixing before it causes problems.
the hpet spec says to set a bit to force a 32-bit counter on 32-bit platforms see 2.4.7 Issues related to 64-bit Timers with 32-bit CPUs, in https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/software-developers-hpet-spec-1-0a.pdf > > ok? > > Index: acpihpet.c > =================================================================== > RCS file: /cvs/src/sys/dev/acpi/acpihpet.c,v > retrieving revision 1.28 > diff -u -p -r1.28 acpihpet.c > --- acpihpet.c 25 Aug 2022 18:01:54 -0000 1.28 > +++ acpihpet.c 9 Sep 2022 01:30:26 -0000 > @@ -281,13 +281,19 @@ acpihpet_attach(struct device *parent, s > void > acpihpet_delay(int usecs) > { > - uint64_t c, s; > + uint64_t count = 0, cycles; > struct acpihpet_softc *sc = hpet_timecounter.tc_priv; > + uint32_t val1, val2; > > - s = acpihpet_r(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER); > - c = usecs * hpet_timecounter.tc_frequency / 1000000; > - while (acpihpet_r(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER) - s < c) > + val2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER); > + cycles = usecs * hpet_timecounter.tc_frequency / 1000000; > + while (count < cycles) { > CPU_BUSY_CYCLE(); > + val1 = val2; > + val2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, > + HPET_MAIN_COUNTER); > + count += val2 - val1; > + } > } > > u_int > >
