[Nix-dev] xserver error "(no mode of this name)"

[Marco Maggesi]

Hi everybody!

I noticed that many important fixes were done to the system  
configuration
of xserver in the past days.  So I decided to updated my system and  
happily
many problem I had since the last upgrade disappeared.
However, I still have a problem with the use of custom VESA modes.

I use NixOS inside VirtualBox and I would like to work with
a resolution of 1440x900.

I set a custom vesa mode and I added a mode line in my xorg.conf
in this way:

     xserver = {
       enable = true;
       exportConfiguration = true;

       videoDriver = "vesa";
       sessionType = "";
       windowManager = "none";
       sessionStarter = "";
       resolutions = [ { x=1440; y=900; } { x=1152; y=864; }
                       { x=1024; y=768; } { x=800; y=600; } ];
       extraMonitorSettings = ''
         Modeline "1440x900" 106.5000 1440 1520 1672 1904 900 903 909  
934 +HSync -VSync
       '';
     };
   };

All this worked fine in an old system profile.

Now, in my current system profile, I get a only the resolution 800x600.
This was partially caused by the fact that the values of horizontal and
vertical frequencies were not properly set.  So I modified the variable
extraMonitorSettings as follows:

       extraMonitorSettings = ''
         HorizSync    24.0-92.0
         VertRefresh  50.0-85.0
         Modeline "1440x900" 106.5000 1440 1520 1672 1904 900 903 909  
934 +HSync -VSync
       '';

So the first question is: what values I should put in HorizSync and  
VertRefresh.
(The values I put were chosen almost at random.)

Anyway, this worked and allowed me to recover at least all the standard
vesa resolutions.
But for the 1440x900 I get the error "no mode of this name".
(See below for and an excerpt of the log file.)

How can I solve this problem?
Thanks,
Marco

PS: NixOS is fantastic!  I can still work with the old profile and try
from times to times to upgrade to the last NixOS version to prepare the
next "stable" version of my working environment.  This is really cool!


-------------------------------------------------------------------------------
cat /var/log/X.0.log
[...]
[...]
(II) VESA(0): VESA VBE DDC not supported
(II) VESA(0): Searching for matching VESA mode(s):
Mode: 100 (640x400)
         ModeAttributes: 0x9b
[...]
[...]
[...]
Mode: 160 (1440x900)
         ModeAttributes: 0x9b
         WinAAttributes: 0x7
         WinBAttributes: 0x0
         WinGranularity: 64
         WinSize: 64
         WinASegment: 0xa000
         WinBSegment: 0x0
         WinFuncPtr: 0xc0007f6f
         BytesPerScanline: 4320
         XResolution: 1440
         YResolution: 900
         XCharSize: 8
         YCharSize: 16
         NumberOfPlanes: 1
         BitsPerPixel: 24
         NumberOfBanks: 1
         MemoryModel: 6
         BankSize: 0
         NumberOfImages: 2
         RedMaskSize: 8
         RedFieldPosition: 16
         GreenMaskSize: 8
         GreenFieldPosition: 8
         BlueMaskSize: 8
         BlueFieldPosition: 0
         RsvdMaskSize: 0
         RsvdFieldPosition: 0
         DirectColorModeInfo: 0
         PhysBasePtr: 0xe0000000

(II) VESA(0): Total Memory: 128 64KB banks (8192kB)
(II) VESA(0): Monitor[0]: Using hsync range of 24.00-92.00 kHz
(II) VESA(0): Monitor[0]: Using vrefresh range of 50.00-85.00 Hz
(II) VESA(0): Not using mode "1440x900" (no mode of this name)
(II) VESA(0): Not using built-in mode "1152x864" (no mode of this name)
(II) VESA(0): Not using built-in mode "1024x768" (no mode of this name)
(II) VESA(0): Not using built-in mode "800x600" (no mode of this name)
(II) VESA(0): Not using built-in mode "1600x1200" (no mode of this name)
(II) VESA(0): Not using built-in mode "1280x1024" (no mode of this name)
(II) VESA(0): Not using built-in mode "640x480" (no mode of this name)
(II) VESA(0): Not using built-in mode "640x400" (no mode of this name)
(II) VESA(0): Not using built-in mode "320x200" (no mode of this name)
(WW) VESA(0): No valid modes left. Trying less strict filter...
(II) VESA(0): Monitor[0]: Using hsync range of 24.00-92.00 kHz
(II) VESA(0): Monitor[0]: Using vrefresh range of 50.00-85.00 Hz
(II) VESA(0): Not using mode "1440x900" (no mode of this name)
(II) VESA(0): Not using built-in mode "1600x1200" (width too large for  
virtual size)
(II) VESA(0): Not using built-in mode "1280x1024" (width too large for  
virtual size)
(II) VESA(0): Not using built-in mode "320x200" (illegal horizontal  
timings)
(--) VESA(0): Virtual size is 1152x864 (pitch 1152)
(**) VESA(0): *Built-in mode "1152x864"
(**) VESA(0): *Built-in mode "1024x768"
(**) VESA(0): *Built-in mode "800x600"
(**) VESA(0):  Built-in mode "640x480"
(**) VESA(0):  Built-in mode "640x400"
(==) VESA(0): DPI set to (96, 96)
(II) VESA(0): Attempting to use 75Hz refresh for mode "1152x864" (14c)
(II) VESA(0): Attempting to use 85Hz refresh for mode "1024x768" (144)
(II) VESA(0): Attempting to use 85Hz refresh for mode "800x600" (143)
(II) VESA(0): Attempting to use 85Hz refresh for mode "640x480" (142)
(II) VESA(0): Attempting to use 85Hz refresh for mode "640x400" (141)
(**) VESA(0): Using "Shadow Framebuffer"
(II) Loading sub module "shadow"
(II) LoadModule: "shadow"

[...]
[...]