Bug 13856

Hi everyone,

I have the following bug on my setup :

toshiba L40 with intel chipset and graphics intel 945GM
samsung syncMaster 225BW (22' monitor with wsxga 1680x1050 rez)

debian lenny updated, i386
- kernel 2.6.23-12, vanilla 
- xorg 1.3.0, 19th april 2007, debian package
- xrandr 1.2

The laptop is packed with a custom vista installation, the intel driver on this platform works for my setup, with samsung .inf file for the monitor. note : using vista only for testing, else I never ever boot it, too slow and crappy ;).

Description of the problem :

xrandr detects screen correctly when plugged as  --output VGA, with standard modes (VESA) well detected. But the maximum resolution I can reach is 1280x1024. using the xrandr-detected modeline --mode 1680x1024 gives random output on the external screen. It seems there is a synchronisation problem with this precise resolution.

on win, the screen is detected with good modeline in its native resolution.

So I tought it was a modeline problem with EDID bad detection. And also, the 1680x1050 rez is not VESA on this screen (samsung doc). So I got modeline from powerstrip, namely
Modeline "1680x1050_test" 146.742 1680 1784 1960 2240 1050 1053 1059 1089 -Hsync +Vsync
And tried to force it to the screen by adding it to xrandr and as a permanent solution, later to xorg.conf.

But even with the good modeline, the screen will keep outputting garbage only in that resolution. The 1280x1024 resolution was not working either with EDID-read settings, but adding a custom modeline, generated with http://xtiming.sourceforge.net/ worked :
Modeline "1280x1024_60" 109.62  1280 1336 1472 1720  1024 1024 1026 1062

So I found reports of wrong EDID detection :
http://softwarecommunity.intel.com/isn/Community/en-US/forums/30246090/ShowThread.aspx
http://softwarecommunity.intel.com/isn/Community/en-US/forums/permalink/30231135/30231179/ShowThread.aspx#30231179

But changing EDID table is not documented as far as I know for the intel graphics linux driver.

And that doesn't change the problem, as we'll see :

I tried 915resolution to force the 1680x1024 resolution in the bios, without sucess, even with the resolution loaded, still garbage on the VGA output. Strangely, the table there was filled only with 1280x800, and still I can change resolution of my xserver without problem, even with two screens in extended desktop mode (rez independent).

I tried to use xvidtune, but it would not be able to select an output to play with, and it would always load settings for LVDS and sometime for the VGA monitor, not useable.

So now I am quite desperate because it won't work on my platform, I cannot use windows and I hope the linux driver can reach the windows ones in term of functionality.

I tried alot before posting here, so I hope my report is clear. Summing it up :

Samsung syncMaster 225BW, 1680x1050 on VGA output 
-> working on windows (intel driver + monitor .inf)
-> garbage output on linux
   -> with EDID-detected modeline
   -> with "good" modeline (not EDID-detected)
      -> does not seem to depend on modeline setting
   -> even with 915resolution forcing mode in bios

I can try anything you tell me, because I've got not idea left :/

Cheers,
Joa