From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: KVM: PIT: support mode 4 Date: Wed, 30 Apr 2008 13:23:54 -0300 Message-ID: <20080430162354.GA25309@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: Avi Kivity Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org 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 https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1952988&group_id=180599 Signed-off-by: Marcelo Tosatti Acked-by: Sheng Yang diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 908520c..1646102 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: ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone