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author | Paolo Bonzini <pbonzini@redhat.com> | 2019-11-17 10:07:38 +0100 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-11-19 10:01:34 +0100 |
commit | 3ae32adff17226bc6a5f3fd7bb9804e6779e0660 (patch) | |
tree | baddc4ff126e778605e2c26a023473b58b8fc23d /hw/rtc/mc146818rtc.c | |
parent | 0d074bf8e74d16920d9c9a132a41d5200333c7bb (diff) | |
download | qemu-3ae32adff17226bc6a5f3fd7bb9804e6779e0660.zip qemu-3ae32adff17226bc6a5f3fd7bb9804e6779e0660.tar.gz qemu-3ae32adff17226bc6a5f3fd7bb9804e6779e0660.tar.bz2 |
Revert "mc146818rtc: fix timer interrupt reinjection"
This reverts commit b429de730174b388ea5760e3debb0d542ea3c261, except
that the reversal of the outer "if (period)" is left in.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/rtc/mc146818rtc.c')
-rw-r--r-- | hw/rtc/mc146818rtc.c | 67 |
1 files changed, 33 insertions, 34 deletions
diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c index ee6bf82..9869dc5 100644 --- a/hw/rtc/mc146818rtc.c +++ b/hw/rtc/mc146818rtc.c @@ -174,7 +174,6 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period) int64_t cur_clock, next_irq_clock, lost_clock = 0; period = rtc_periodic_clock_ticks(s); - if (!period) { s->irq_coalesced = 0; timer_del(s->periodic_timer); @@ -197,42 +196,42 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period) last_periodic_clock = next_periodic_clock - old_period; lost_clock = cur_clock - last_periodic_clock; assert(lost_clock >= 0); + } + /* + * s->irq_coalesced can change for two reasons: + * + * a) if one or more periodic timer interrupts have been lost, + * lost_clock will be more that a period. + * + * b) when the period may be reconfigured, we expect the OS to + * treat delayed tick as the new period. So, when switching + * from a shorter to a longer period, scale down the missing, + * because the OS will treat past delayed ticks as longer + * (leftovers are put back into lost_clock). When switching + * to a shorter period, scale up the missing ticks since the + * OS handler will treat past delayed ticks as shorter. + */ + if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) { + uint32_t old_irq_coalesced = s->irq_coalesced; + + s->period = period; + lost_clock += old_irq_coalesced * old_period; + s->irq_coalesced = lost_clock / s->period; + lost_clock %= s->period; + if (old_irq_coalesced != s->irq_coalesced || + old_period != s->period) { + DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, " + "period scaled from %d to %d\n", old_irq_coalesced, + s->irq_coalesced, old_period, s->period); + rtc_coalesced_timer_update(s); + } + } else { /* - * s->irq_coalesced can change for two reasons: - * - * a) if one or more periodic timer interrupts have been lost, - * lost_clock will be more that a period. - * - * b) when the period may be reconfigured, we expect the OS to - * treat delayed tick as the new period. So, when switching - * from a shorter to a longer period, scale down the missing, - * because the OS will treat past delayed ticks as longer - * (leftovers are put back into lost_clock). When switching - * to a shorter period, scale up the missing ticks since the - * OS handler will treat past delayed ticks as shorter. + * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW + * is not used, we should make the time progress anyway. */ - if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) { - uint32_t old_irq_coalesced = s->irq_coalesced; - - s->period = period; - lost_clock += old_irq_coalesced * old_period; - s->irq_coalesced = lost_clock / s->period; - lost_clock %= s->period; - if (old_irq_coalesced != s->irq_coalesced || - old_period != s->period) { - DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, " - "period scaled from %d to %d\n", old_irq_coalesced, - s->irq_coalesced, old_period, s->period); - rtc_coalesced_timer_update(s); - } - } else { - /* - * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW - * is not used, we should make the time progress anyway. - */ - lost_clock = MIN(lost_clock, period); - } + lost_clock = MIN(lost_clock, period); } assert(lost_clock >= 0 && lost_clock <= period); |