Bug 301417

Summary: missing sync tolerance in Xserver
Product: [openSUSE] openSUSE 10.3 Reporter: Andreas Jaeger <aj>
Component: X.OrgAssignee: Matthias Hopf <mhopf>
Status: RESOLVED FIXED QA Contact: E-mail List <qa-bugs>
Severity: Enhancement    
Priority: P5 - None    
Version: Beta 1   
Target Milestone: ---   
Hardware: Other   
OS: Other   
Whiteboard:
Found By: --- Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---
Attachments: SaX.log
xorg.conf
xorg log from sax2 run

Description Andreas Jaeger 2007-08-17 16:22:40 UTC 
My Laptop has a buildin 1024x768 config file but sax2 will write a config so that X will start with 800x600.

Note: this worked with beta1 - but today's build (20080717) with sax2-8.1-206 does not work.
Comment 1 Andreas Jaeger 2007-08-17 16:24:29 UTC 
Created attachment 158248 [details]
SaX.log
Comment 2 Andreas Jaeger 2007-08-17 16:26:11 UTC 
Created attachment 158250 [details]
xorg.conf
Comment 3 Andreas Jaeger 2007-08-17 16:26:36 UTC 
Created attachment 158251 [details]
xorg log from sax2 run
Comment 4 Stefan Dirsch 2007-08-17 16:44:01 UTC 
Probably a duplicate of Bug #270846.
Comment 5 Marcus Schaefer 2007-08-19 20:10:04 UTC 
yes probably a problem with the new randr data. I need this system
for a ssh login and the possibility to install packages with yast -i ...

would that be possible

Thanks
Comment 7 Marcus Schaefer 2007-08-20 08:39:37 UTC 
I called sax2 -r -a on the machine and the config looks ok to me
The Xorg log said:

  (II) intel(0): Output LVDS using initial mode 1024x768

I'm remote so I don't know whether it starts with that resolution or
not.

Stefan , Andreas ?
Comment 8 Andreas Jaeger 2007-08-20 08:54:39 UTC 
Looks ok now - as discussed via phone.
Comment 9 Marcus Schaefer 2007-08-20 09:35:19 UTC 

*** This bug has been marked as a duplicate of bug 270846 ***
Comment 10 Matthias Hopf 2007-08-20 13:20:53 UTC 
The issue is that the 1024x768 mode is *slightly* above 60Hz (60.01Hz, to be specific), and up to now the monitor section was completely ignored (RandR 1.2 uses a different notion for monitors). The monitor section specifies the horizontal range to 50-60 Hz, so 60.01Hz is no longer acceptable...

I already said a long time ago that probably 58-62 or 55-65 Hz for the default monitors would be a better range to cope for future mode validation changes.

One could also argue that the xserver should allow for .5 Hz variations. We'll probably discuss this tomorrow.
Comment 11 Marcus Schaefer 2007-08-20 13:50:45 UTC 
I have added the 60 Hz sharp because people told me that for TFT
displays this is a must have and many of them complain if you give it
a higher range... so some people say that and some others say that
Comment 12 Matthias Hopf 2007-08-20 14:10:33 UTC 
Which is wrong, of course, because PLLs can never be programmed to behave *exactly* at a given frequency. They can always be up to +/- 0.1-2 % off (depending on brand and type).

But the monitor actually specifies a range (50-60), so this cannot be the case here.

Again, 59-61 or 58-62 would be probably fine, having the Xserver specifically add/subtract 1% or 0.5 absolute would be another option.
Comment 13 Matthias Hopf 2007-08-27 15:46:11 UTC 
Comment from Ajax:

> The classic mode selection code has some tolerance already.  In
> xf86str.h:
>
> #define SYNC_TOLERANCE          0.01    /* 1 percent */
>
> Which seems to have served us well.  So I'd prefer to either have the
> new mode code use the same fuzz, or else change it in both places.

So I'll use this tolerance instead for upstream.
Comment 14 Matthias Hopf 2007-08-27 15:46:46 UTC 
Reopening so this is not lost for upstream.
Comment 15 Matthias Hopf 2007-10-12 17:05:31 UTC 
Fixed upstream.

Stefan, the upstream fix is different (SYNC_TOLERANCE - this is relative not absolute), so on next update you will want to nuke this patch.