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authorMarcelo Tosatti <mtosatti@redhat.com>2008-04-30 13:23:54 -0300
committerAvi Kivity <avi@qumranet.com>2008-05-04 14:44:46 +0300
commitece15babfa514e06118f62f4df2c757d6209f4f0 (patch)
tree46eadfa87b6adb88a2252c15f0468e8330968001 /arch/x86
parentdc7457ea52f88539dc72925360e6068d5c938a0f (diff)
KVM: PIT: support mode 4
The in-kernel PIT emulation ignores pending timers if operating under mode 4, which for example DragonFlyBSD uses (and Plan9 too, apparently). Mode 4 seems to be similar to one-shot mode, other than the fact that it starts counting after the next CLK pulse once programmed, while mode 1 starts counting immediately, so add a FIXME to enhance precision. Fixes sourceforge bug 1952988. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Acked-by: Sheng Yang <sheng.yang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/i8254.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 4c943eabacc3..3324d90038e4 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -288,6 +288,8 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
* mode 1 is one shot, mode 2 is period, otherwise del timer */
switch (ps->channels[0].mode) {
case 1:
+ /* FIXME: enhance mode 4 precision */
+ case 4:
create_pit_timer(&ps->pit_timer, val, 0);
break;
case 2: