Attachment 33963 Details for Bug 27023 – Fix incorrect calculation of bracket values when startOver = FALSE

[patch] Fix incorrect calculation of bracket values when startOver = FALSE

0001-Fix-incorrect-calculation-of-bracket-values-when-sta.patch (text/plain), 4.27 KB, created by David James on 2010-03-11 11:15:25 UTC

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Creator: David James

Created: 2010-03-11 11:15:25 UTC

Size: 4.27 KB

patch

obsolete

>From ed5b62184ca07005afc63522cd518ae754d71c9b Mon Sep 17 00:00:00 2001
>From: David James <davidjames@google.com>
>Date: Thu, 11 Mar 2010 10:36:37 -0800
>Subject: [PATCH] Fix incorrect calculation of bracket values when startOver = FALSE.
> Currently, SyncComputeBracketValues reuses old values of bracket_greater
> and bracket_less when startOver = FALSE. This can result in incorrect bracket
> values. To fix this issue, the startOver parameter is removed, and we do not
> reuse old values of bracket_greater and bracket_less.
>
>X.Org Bug 18668 <http://bugs.freedesktop.org/show_bug.cgi?id=27023>
>---
> Xext/sync.c |   19 ++++++++-----------
> 1 files changed, 8 insertions(+), 11 deletions(-)
>
>diff --git a/Xext/sync.c b/Xext/sync.c
>index ce65314..2015fc1 100644
>--- a/Xext/sync.c
>+++ b/Xext/sync.c
>@@ -94,7 +94,7 @@ static SyncCounter **SysCounterList = NULL;
> #define XSyncCAAllTrigger \
>     (XSyncCACounter | XSyncCAValueType | XSyncCAValue | XSyncCATestType)
> 
>-static void SyncComputeBracketValues(SyncCounter *, Bool);
>+static void SyncComputeBracketValues(SyncCounter *);
> 
> static void SyncInitServerTime(void);
> 
>@@ -167,7 +167,7 @@ SyncDeleteTriggerFromCounter(SyncTrigger *pTrigger)
>     }
> 
>     if (IsSystemCounter(pTrigger->pCounter))
>-	SyncComputeBracketValues(pTrigger->pCounter, /*startOver*/ TRUE);
>+	SyncComputeBracketValues(pTrigger->pCounter);
> }
> 
> 
>@@ -194,7 +194,7 @@ SyncAddTriggerToCounter(SyncTrigger *pTrigger)
>     pTrigger->pCounter->pTriglist = pCur;
> 
>     if (IsSystemCounter(pTrigger->pCounter))
>-	SyncComputeBracketValues(pTrigger->pCounter, /*startOver*/ TRUE);
>+	SyncComputeBracketValues(pTrigger->pCounter);
> 
>     return Success;
> }
>@@ -351,7 +351,7 @@ SyncInitTrigger(ClientPtr client, SyncTrigger *pTrigger, XSyncCounter counter,
>     }
>     else if (IsSystemCounter(pCounter))
>     {
>-	SyncComputeBracketValues(pCounter, /*startOver*/ TRUE);
>+	SyncComputeBracketValues(pCounter);
>     }
> 
>     return Success;
>@@ -646,7 +646,7 @@ SyncChangeCounter(SyncCounter *pCounter, CARD64 newval)
> 
>     if (IsSystemCounter(pCounter))
>     {
>-	SyncComputeBracketValues(pCounter, /* startOver */ FALSE);
>+	SyncComputeBracketValues(pCounter);
>     }
> }
> 
>@@ -913,7 +913,7 @@ SyncDestroySystemCounter(pointer pSysCounter)
> }
> 
> static void
>-SyncComputeBracketValues(SyncCounter *pCounter, Bool startOver)
>+SyncComputeBracketValues(SyncCounter *pCounter)
> {
>     SyncTriggerList *pCur;
>     SyncTrigger *pTrigger;
>@@ -930,11 +930,8 @@ SyncComputeBracketValues(SyncCounter *pCounter, Bool startOver)
>     if (ct == XSyncCounterNeverChanges)
> 	return;
> 
>-    if (startOver)
>-    {
>-	XSyncMaxValue(&psci->bracket_greater);
>-	XSyncMinValue(&psci->bracket_less);
>-    }
>+    XSyncMaxValue(&psci->bracket_greater);
>+    XSyncMinValue(&psci->bracket_less);
> 
>     for (pCur = pCounter->pTriglist; pCur; pCur = pCur->next)
>     {
>-- 
>1.7.0.1
>
>Reproduction recipe:
>  1. Setup a positive transition alarm for when idle time exceeds 2000ms
>  2. Setup a positive transition alarm for when idle time exceeds 5000ms
>  3. Become idle, and wait for the alarms to trigger.
>
>Expected result:
>  - When idle time exceeds 2000ms, the first alarm triggers.
>  - When idle time exceeds 5000ms, the second alarm triggers.
>
>Actual result:
>  - When idle time exceeds 2000ms, the first alarm triggers.
>  - When idle time exceeds 5000ms, the second alarm does not trigger.
>
>Analysis:
>
> 1) When you first setup the alarms, the SyncComputeBracketValues function is
>called with startOver = TRUE. In this case, the bracket values are calculated
>correctly, and the member variable "bracket_greater" on the idle time counter
>is set to 2000.
> 2) When the first alarm triggers, the SyncComputeBracketValues function is
>called with startOver = FALSE, from SyncChangeCounter. In this case, the second
>alarm should be set up, and the member variable "bracket_greater" on the idle
>time counter should be set to 5000. However, because the test value (5000) is
>greater than the previous value of bracket_greater (2000), this alarm is not
>enabled.
>
>Solution:
>
>To fix this problem, I updated the SyncChangeCounter function to call
>SyncComputeBracketValues with startOver = TRUE. This causes "bracket_greater"
>to be reset and the alarm to be triggered correctly. After doing this, the
>startOver variable is always set to TRUE, so I also cleaned up the code and
>eliminated this parameter altogether.
>

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