Bugzilla – Bug 508534
sax2: generates broken modeline for 1366x768 (50 Hz!)
Last modified: 2009-06-03 16:52:18 UTC
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.10) Gecko/2009042700 SUSE/3.0.10-1.1.1 Firefox/3.0.10 On first installation, SAX2 configured the display as 800x600. I had to reconfigure it by selecting the correct resolution of 1366x760. However, after doing this, the screen is slightly unclear. It turns out that SAX2 has manually added this mode line to my xorg.conf: Modeline "1366x768" 69.92 1368 1424 1568 1768 768 769 772 791 Which is the one producing the slight waving across the display. When X starts, the panel EDID recommends this mode (which gets ignored): (II) intel(0): Printing DDC gathered Modelines: (II) intel(0): Modeline "1366x768"x0.0 72.30 1366 1414 1446 1526 768 771 776 790 +hsync -vsync (47.4 kHz) When I use xrandr to install this mode, the waviness goes and the panel becomes clear. So, two questions: 1) Why is SaX2 even trying to install a modeline? For modern X we can simply rely on picking up the panel EDID information ... there's no need to override anything 2) When the panel clearly supplies an EDID entry for the correct mode, why is it being ignored Reproducible: Always Steps to Reproduce: 1. Use SaX to reconfigure the display 2. 3. Actual Results: We end up with the slightly fuzzy 50Hz screen Expected Results: We should end up with the crisp 60HZ screen recommended by EDID
I agree. We no longer want to overwrite EDID recommendations. *** This bug has been marked as a duplicate of bug 441404 ***
I agree this bug would be fixed by the enhancement, but it's a bug now. The 50Hz modeline causes the panel to be wavy and out of focus. That's wrong now and needs fixing now otherwise customers with the HP mini K series will hate the experience openSUSE gives them. If it needs to be added to some database so SaX 2 produces the proper panel mode line until such time as the enhancement request is in, then that would be a reasonable way to fix this
Ouch! Indeed this modeline looks broken (50Hz for a LVDS panel!). Unfortunately I can't reproduce that issue. What did you exactly in SaX2? Marcus, any ideas where this modeline comes from?
Created attachment 295734 [details] xorg.conf generated by SaX
This was from a fresh install of OpenSUSE 11.1 which brought up the display in 800x600. On reboot, I used yast to fire up SaX to reconfigure this to 1366x768 which is the correct panel resolution. That's when it gave me the 50Hz modeline. Looking through the generated conf file (attached) I see this: HorizSync 29-40 Which is too low to support 1366 @ 60Hz (Needs to be about 48 at the top end), so it could be this which is the root cause.
I don't see a modeline in the latest xorg.conf, you've attached. Indeed 29-40 kHz is no sufficient for such a mode. Maybe you've configured the mode, but not an appropriate monitor in SaX2 ?!? This is the reason I asked for a detailed description how you configured the 1366x768 mode in SaX2.
Sorry, must have been half way through fixing the problem when I saved the xorg.conf file ... I don't seem to have a pristine original. I configured it as I said above ... I didn't set a monitor: it's an LCD panel and should be auto detected, I just went straight to the resolution and fixed that. When I go to Configure Display Settings, it said Monitor: Laptop 10" Which sounded reasonable, so I left it. I just altered the resolution on the resolution button, which seems like the natural thing to do.
Well, the issue was, that the panel/monitorhas *not* been autodetected. Don't know where this 'Laptop 10"' information comes from, but it appears to be a misinformation. I'm rather sure that a monitor has been selected with 29-40 kHz, 48-75Hz. Then you just changed the resolution setting, which then ended up in a 50Hz modeline. This might be not what you've expected, but IMHO at least a consistens behaviour. Especially if I need to assume that SaX2 even didn't know that it's laptop behind. So I suggest to select the right LCD monitor (Vendor: LCD, Name: 1366x768@60HZ) as well. Is it working then?
OK, I can't reinstall the system, but I can blow away the configuration and try again. The default SaX2 installation gives the attached configuration at 800x600 ... this is the one that has the monitor horizontal refresh too low. Since this is given at install time, there's no way to modify it. Next, when you log in, reconfigure display is handled by the 'Configure Display settings' applet. It's this that tells me I have a 10" monitor and allows me to set the resolution, and when I set it to 1366x768 it's at too low a refresh rate. So the problem is that we get into this situation on the default path a user would use to configure the system. If I ignore the display panel applet and fire up SaX2 again, I can then see it has an unknown monitor and set it to a 1366x768@60Hz panel ... but a causal user wouldn't know to do this, which is why this is a usability bug.
Created attachment 295990 [details] Xorg.conf generated by the SaX default configuration
(In reply to comment #9) > OK, I can't reinstall the system, but I can blow away the configuration and try > again. The default SaX2 installation gives the attached configuration at > 800x600 ... this is the one that has the monitor horizontal refresh too low. > Since this is given at install time, there's no way to modify it. You can't change it during installation if you chose autoconfiguration for installation (which is our default). Afterwards you can change it via YaST/SaX2. > Next, when you log in, reconfigure display is handled by the 'Configure Display > settings' applet. It's this that tells me I have a 10" monitor and allows me > to set the resolution, and when I set it to 1366x768 it's at too low a refresh > rate. This is a different tool. Either krandrtray (KDE4) or gnome-display-properties (Gnome). I think these tools can't change the hsync/vsync limits of the monitor, so it's possible that they offer such modelines. > So the problem is that we get into this situation on the default path a user > would use to configure the system. > > If I ignore the display panel applet and fire up SaX2 again, I can then see it > has an unknown monitor and set it to a 1366x768@60Hz panel ... but a causal > user wouldn't know to do this, which is why this is a usability bug. Again. We need to get rid of xorg.conf/sax2, but it's not possible to fix this still for 11.1. *** This bug has been marked as a duplicate of bug 441404 ***