Le 10/03/2021 à 13:56, Laurent Vivier a écrit : > Le 10/03/2021 à 13:32, BALATON Zoltan a écrit : >> On Wed, 10 Mar 2021, Mark Cave-Ayland wrote: >>> The 60Hz timer is initialised using timer_new_ns() meaning that the timer >>> interval should be measured in ns, and therefore its period is a thousand >>> times too short. >>> >>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk> >>> --- >>> hw/misc/mac_via.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c >>> index f994fefa7c..c6e1552a59 100644 >>> --- a/hw/misc/mac_via.c >>> +++ b/hw/misc/mac_via.c >>> @@ -302,8 +302,8 @@ static void via1_sixty_hz_update(MOS6522Q800VIA1State >>> *v1s) >>> MOS6522State *s = MOS6522(v1s); >>> >>> /* 60 Hz irq */ >>> - v1s->next_sixty_hz = (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 16630) / >>> - 16630 * 16630; >>> + v1s->next_sixty_hz = (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + >>> 16630000) / >>> + 16630000 * 16630000; >> >> Can you put this magic number in a #define maybe also rewriting it in a way >> that shows it >> corresponds to a 60 Hz interval. (There's NANOSECONDS_PER_SECOND defined in >> include/qemu/timer.h >> that could be used for that, there's also SCALE_MS that might replace 1000 * >> 1000 elsewhere in this >> file). Also NANOSECONDS_PER_SECOND / 60 is 16666666, should that value be >> used here instead? > > In fact, the Mac Frequency is not exactly 60 Hz, in docs we can find 60.147 > Hz, in kernel 60.15 Hz. > I Think there are several ways to compute it... >
In fact, we can read: "the vertical retrace frequency is approximately 60.15 Hz, resulting in a period of approximately 16.63 milliseconds" https://developer.apple.com/library/archive/documentation/mac/pdf/Processes/Vertical_Retrace_Mgr.pdf Thanks, Laurent
