Bug 15597

Summary:	Strange KDE panel shadow.
Product:	Mageia	Reporter:	Renato Dali <mkare>
Component:	RPM Packages	Assignee:	Mageia Bug Squad <bugsquad>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	Normal
Version:	Cauldron
Target Milestone:	---
Hardware:	i586
OS:	Linux
Whiteboard:
Source RPM:		CVE:
Status comment:
Attachments:	Phantom panel outline (at left). dmesg output Xorg.0.log contents.

Description Renato Dali 2015-03-31 06:10:56 CEST

Created attachment 6165 [details]
Phantom panel outline (at left).

I'm using an auto-hiding panel which is working well in the present configuration with the oxygen theme. There's a bug affecting its workings if the theme "Air for notebooks" is selected (bug 15547 ).

I've noticed there's an outline where the panel would be if it were shown (please see attached pic).

This outline is triggered after the panel is made to come up and hide again. The screenshot was taken with the cursor over the trash bin; this is one way to make it last more. It usually disappears by itself.

Unless a cursor (like "|") is blinking and data being entered (just like at this moment I'm writing)... in that situation, the outline blinks in the same frequency as the text cursor. Once I coincidentally noticed they were in sync and in phase. Afterwards I noticed it blinks with the same frequency but out of phase, too.

Inside the text field: it blinks; clicking on the gray area in this site (outside the "Description" text field: it becomes steady and visible if mouse over text field -- or invisible if mouse outside of text field.

I'm using Nouveau (attached: dmesg and Xorg.0.log)

Desktop effects are deactivated; advanced tab says OpenGL 1.2, Native Qt Graphics, scaling = crisp. turning Vsync tearing prevention seems to affect frequency of blinking.

The outline does not appear for horizontal panels; it appears also with the panel on the right side of the screen.

Possible workarounds are:

- use the panel at left without auto-hiding;

- use the panel at the bottom with auto-hiding.

Comment 1 Renato Dali 2015-03-31 06:11:44 CEST

Created attachment 6166 [details]
dmesg output

Comment 2 Renato Dali 2015-03-31 06:12:58 CEST

Created attachment 6167 [details]
Xorg.0.log contents.

Comment 3 Renato Dali 2015-04-01 01:21:45 CEST

This problem seems to be related to vsync, as suspected.

Today, after booting the PC, I noticed the problem was gone.

I could trigger it just by changing "tearing prevention (vsync)" from "none" to "only when economic" or "full picture update" (sorry if English text not correct -- I'm reading in Portuguese).

To return things to normal, one has to reset vsync to none _and_ log off the session. Just resetting vsync is not enough.

This might require further testing to evaluate the possibility of a buffering problem, either in Nouveau or Mesa.

Comment 4 Renato Dali 2015-04-02 01:11:32 CEST

Hmm, not that simple.

I turned on desktop effects again -- with vsync off -- and the problem returned. :-/

Turning BackingStore off in xorg.conf didn't help. I then proceeded to turn off the active affects, one by one.

When I turned off "Sliding Instant Messages" the problem went away. Now I'm using my Geforce 6200 with Nouveau, BackingStore on, a bunch of effects (some 17 probably)  and the following settings in Desktop Effects/Advanced:

Composition: OpenGL 1.2 (Nouveau dislikes 2.0 on this card, I concluded in bug 15462 .
Qt graphics system: Native

Miniatures: Just for visible screens
Scaleing method: Crisp
[ ] Suspend effects on full screen (unselected)
Tearing prevention (VSync): Total scene update (translated back, maybe wrong)

So far, no problems. I'll report later whether this is a solution or not.

Comment 5 Renato Dali 2015-04-18 19:08:10 CEST

Today I turned on "Sliding Instant Messages" back on and could not verify the bug again.

It might already be solved, another package might have been the cause and was fixed or maybe it's the fact I've installed some KDE themes.

Even after rebooting, without any change in xorg.conf or vsync use, the bug does not come up.

I will test KDE for some days to confirm whether the bug still exists.

Comment 6 Renato Dali 2015-04-27 06:57:56 CEST

"Sliding Instant Messages" has been on for some time and no sign of the bug anymore.

Maybe someone fixed it (intently or not) or perhaps I installed some package which has made the problem disappear (certainly without intent).

Comment 7 Samuel Verschelde 2015-04-27 09:11:51 CEST

Thanks. I'm closing it since it appears fixed and will be hard to reproduce if it isn't. Just reopen it if it happens again.

Status: NEW => RESOLVED
Resolution: (none) => FIXED

Comment 8 Renato Dali 2015-04-27 18:32:46 CEST

Ok, thanks.