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[Qemu-devel] [5199] uhci: Change default transaction lifetime to 32 fram
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [5199] uhci: Change default transaction lifetime to 32 frames ( Max Krasnyansky) |
Date: |
Thu, 11 Sep 2008 19:42:00 +0000 |
Revision: 5199
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5199
Author: aliguori
Date: 2008-09-11 19:42:00 +0000 (Thu, 11 Sep 2008)
Log Message:
-----------
uhci: Change default transaction lifetime to 32 frames (Max Krasnyansky)
Transaction lifetime was originally set to 10 frames. That was an arbitrary
number I picked without much thinking :).
I'm changing that to 32 frames because things like interrupt transfers
and such are scheduled at that rate. It seems like 1/32 is accepted as
lowest supported rate. OHCI, for example, defines exactly 32 interrupt
heads.
While testing USB webcam under XP I noticed that interrupt transactions were
being canceled and then resubmitted on a regular basis, which works but is a
waste of CPU cycles. This change fixes that.
All other devices I have are not affected.
Signed-off-by: Max Krasnyansky <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
Modified Paths:
--------------
trunk/hw/usb-uhci.c
Modified: trunk/hw/usb-uhci.c
===================================================================
--- trunk/hw/usb-uhci.c 2008-09-11 18:16:02 UTC (rev 5198)
+++ trunk/hw/usb-uhci.c 2008-09-11 19:42:00 UTC (rev 5199)
@@ -781,7 +781,7 @@
async = uhci_async_find_td(s, addr, td->token);
if (async) {
/* Already submitted */
- async->valid = 10;
+ async->valid = 32;
if (!async->done)
return 1;
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