From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: KVM <kvm@qumranet.com>,
Roni Luxenberg <roni.luxenberg@qumranet.com>,
Arnon Gilboa <arnon.gilboa@qumranet.com>
Subject: Re: [Qemu-devel] [PATCH] USB 2.0 EHCI emulation
Date: Tue, 8 Jan 2008 01:30:02 +0000 [thread overview]
Message-ID: <200801080130.04161.paul@codesourcery.com> (raw)
In-Reply-To: <64F9B87B6B770947A9F8391472E0321610478FD1@ehost011-8.exch011.intermedia.net>
> -The host kernel was configured with dynamic tick & hi-res timers, to
> allow the desired timer resolution. USB 2.0 microframe is 125usec.
Requiring a 8kHz timer is a non-starter.
The 100kHz "retry" timer is even more bogus.
Qemu isn't capable of this kind of realtime response. You need to figure out
an implementation that doesn't require extremely fine grained timers. In
paractice you're unlikely to get better than 10ms timer resolution, and 100ms
latency isn't that uncommon.
Paul
next prev parent reply other threads:[~2008-01-08 1:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-07 17:41 [Qemu-devel] [PATCH] USB 2.0 EHCI emulation Arnon Gilboa
2008-01-08 1:30 ` Paul Brook [this message]
2008-01-08 8:31 ` Arnon Gilboa
2008-01-08 8:43 ` Dor Laor
2008-01-08 15:31 ` Paul Brook
2008-01-08 17:14 ` Avi Kivity
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