Bug 13962

Summary:	dpms stops working after disabling and re-enabling it
Product:	xorg	Reporter:	Gilles Hamel <hamelg>
Component:	Server/General	Assignee:	Xorg Project Team <xorg-team>
Status:	RESOLVED FIXED	QA Contact:	Xorg Project Team <xorg-team>
Severity:	normal
Priority:	medium	CC:	alexdeucher, esigra, tiagomatos, yuri
Version:	7.3 (2007.09)
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Bug Depends on:
Bug Blocks:	10101

Description Gilles Hamel 2008-01-07 23:26:13 UTC

Here is how to reproduce :

1. Change dpms setup to a very short delay, say 10s :
   xset dpms 0 0 10 ; sleep 11

2. Wait 10s, the display switches off

3. Disable dpms :
   xset -dpms ; sleep 11

4. Wait 10s, the display remains on 

5. Re-enable dpms :
   xset +dpms ; sleep 11

6. Here, the display stays on, dpms should turns off the display, but it don't. Dpms stops working.

This behavior is not related to a specific driver. It is identical on my desktop with mga_drv and on my laptop with ati_drv.

Comment 1 Gilles Hamel 2008-01-10 13:00:07 UTC

Bug found !

If the timeout occurs when dpms is disabled, ScreenSaverTimeoutExpire() is called and return nextTimeout=0. When you re-enable dpms, ScreenSaverTimeoutExpire() is no more called and dpms stops working until you force or change settings.

To fix that, I have modified ProcDPMSEnable() in Xext/dpms.c.

replace :
    if (DPMSCapableFlag)
	  DPMSEnabled = TRUE;

by :
    if (DPMSCapableFlag) {
	  DPMSEnabled = TRUE;

	  // Reset Timer
	  SetScreenSaverTimer();
     }

Comment 2 Michel Dänzer 2008-01-19 01:44:31 UTC

*** Bug 11922 has been marked as a duplicate of this bug. ***

Comment 3 Michel Dänzer 2008-01-19 01:48:53 UTC

Can somebody review this patch and push it if it looks good?

Comment 4 Alex Deucher 2008-01-19 07:56:28 UTC

Looks ok to me, but I don't really know the server side dpms code at all.  I'll apply it if no one has any objections over the next few days.

Comment 5 Erik 2008-02-27 00:38:05 UTC

This is the bug that has annoyed me for a long time!

Comment 6 Alex Deucher 2008-02-27 07:08:38 UTC

making a 7.4 blocker

Comment 7 Adam Jackson 2008-03-24 09:24:24 UTC

Fixed in master with a slight tweak.  We'll only re-arm the timer if we were disabled before entering ProcDPMSEnable().

Thanks!

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