J’ai récupéré les logs de la machine capricieuse. Sur le Xorg.0.log on voit un warning (ligne 62) concernant un module qui ne se charge pas. Et on constate (ligne 194) que la résolution que je recherche est bien “connue” du système. Voici le début du fichier (pour les autres logs, je ne sais pas quoi y chercher et je ne peux quand même pas les copier en entier…) :
[ 19.394]
X.Org X Server 1.19.2
Release Date: 2017-03-02
[ 19.394] X Protocol Version 11, Revision 0
[ 19.394] Build Operating System: Linux 4.9.0-8-amd64 i686 Debian
[ 19.394] Current Operating System: Linux pc-gerard 4.9.0-8-686-pae #1 SMP Debian 4.9.130-2 (2018-10-27) i686
[ 19.394] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.9.0-8-686-pae root=UUID=49e3efd3-49e4-458d-90f1-4562d45ca45f ro quiet
[ 19.394] Build Date: 03 November 2018 03:08:43AM
[ 19.394] xorg-server 2:1.19.2-1+deb9u5 (https://www.debian.org/support)
[ 19.394] Current version of pixman: 0.34.0
[ 19.394] Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[ 19.394] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 19.395] (==) Log file: "/var/log/Xorg.0.log", Time: Tue Jan 8 13:57:08 2019
[ 19.498] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 19.548] (==) No Layout section. Using the first Screen section.
[ 19.549] (==) No screen section available. Using defaults.
[ 19.549] (**) |-->Screen "Default Screen Section" (0)
[ 19.549] (**) | |-->Monitor "<default monitor>"
[ 19.568] (==) No monitor specified for screen "Default Screen Section".
Using a default monitor configuration.
[ 19.568] (==) Automatically adding devices
[ 19.568] (==) Automatically enabling devices
[ 19.568] (==) Automatically adding GPU devices
[ 19.568] (==) Max clients allowed: 256, resource mask: 0x1fffff
[ 19.648] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[ 19.648] Entry deleted from font path.
[ 19.687] (==) FontPath set to:
/usr/share/fonts/X11/misc,
/usr/share/fonts/X11/100dpi/:unscaled,
/usr/share/fonts/X11/75dpi/:unscaled,
/usr/share/fonts/X11/Type1,
/usr/share/fonts/X11/100dpi,
/usr/share/fonts/X11/75dpi,
built-ins
[ 19.687] (==) ModulePath set to "/usr/lib/xorg/modules"
[ 19.687] (II) The server relies on udev to provide the list of input devices.
If no devices become available, reconfigure udev or disable AutoAddDevices.
[ 19.687] (II) Loader magic: 0x75d720
[ 19.687] (II) Module ABI versions:
[ 19.687] X.Org ANSI C Emulation: 0.4
[ 19.687] X.Org Video Driver: 23.0
[ 19.687] X.Org XInput driver : 24.1
[ 19.687] X.Org Server Extension : 10.0
[ 19.690] (++) using VT number 7
[ 19.690] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[ 19.691] (--) PCI:*(0:1:0:0) 1106:7205:1509:9056 rev 1, Mem @ 0xd8000000/67108864, 0xdc000000/16777216, BIOS @ 0x????????/131072
[ 19.697] (II) LoadModule: "glx"
[ 19.772] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 19.971] (II) Module glx: vendor="X.Org Foundation"
[ 19.971] compiled for 1.19.2, module version = 1.0.0
[ 19.972] ABI class: X.Org Server Extension, version 10.0
[ 19.972] (==) Matched openchrome as autoconfigured driver 0
[ 19.972] (==) Matched modesetting as autoconfigured driver 1
[ 19.972] (==) Matched fbdev as autoconfigured driver 2
[ 19.972] (==) Matched vesa as autoconfigured driver 3
[ 19.972] (==) Assigned the driver to the xf86ConfigLayout
[ 19.972] (II) LoadModule: "openchrome"
[ 19.972] (WW) Warning, couldn't open module openchrome
[ 19.972] (II) UnloadModule: "openchrome"
[ 19.972] (II) Unloading openchrome
[ 19.972] (EE) Failed to load module "openchrome" (module does not exist, 0)
[ 19.972] (II) LoadModule: "modesetting"
[ 19.973] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[ 20.124] (II) Module modesetting: vendor="X.Org Foundation"
[ 20.125] compiled for 1.19.2, module version = 1.19.2
[ 20.125] Module class: X.Org Video Driver
[ 20.125] ABI class: X.Org Video Driver, version 23.0
[ 20.125] (II) LoadModule: "fbdev"
[ 20.125] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[ 20.172] (II) Module fbdev: vendor="X.Org Foundation"
[ 20.172] compiled for 1.19.0, module version = 0.4.4
[ 20.172] Module class: X.Org Video Driver
[ 20.172] ABI class: X.Org Video Driver, version 23.0
[ 20.172] (II) LoadModule: "vesa"
[ 20.172] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
[ 20.205] (II) Module vesa: vendor="X.Org Foundation"
[ 20.205] compiled for 1.19.0, module version = 2.3.4
[ 20.205] Module class: X.Org Video Driver
[ 20.205] ABI class: X.Org Video Driver, version 23.0
[ 20.205] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[ 20.205] (II) FBDEV: driver for framebuffer: fbdev
[ 20.205] (II) VESA: driver for VESA chipsets: vesa
[ 20.211] (EE) open /dev/dri/card0: No such file or directory
[ 20.211] (WW) Falling back to old probe method for modesetting
[ 20.211] (EE) open /dev/dri/card0: No such file or directory
[ 20.211] (II) Loading sub module "fbdevhw"
[ 20.211] (II) LoadModule: "fbdevhw"
[ 20.211] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 20.232] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 20.232] compiled for 1.19.2, module version = 0.0.2
[ 20.232] ABI class: X.Org Video Driver, version 23.0
[ 20.232] (EE) open /dev/fb0: No such file or directory
[ 20.232] (WW) Falling back to old probe method for fbdev
[ 20.232] (II) Loading sub module "fbdevhw"
[ 20.232] (II) LoadModule: "fbdevhw"
[ 20.232] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 20.233] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 20.233] compiled for 1.19.2, module version = 0.0.2
[ 20.233] ABI class: X.Org Video Driver, version 23.0
[ 20.233] (EE) open /dev/fb0: No such file or directory
[ 20.233] (EE) Screen 0 deleted because of no matching config section.
[ 20.233] (II) UnloadModule: "modesetting"
[ 20.233] (EE) Screen 0 deleted because of no matching config section.
[ 20.233] (II) UnloadModule: "fbdev"
[ 20.233] (II) UnloadSubModule: "fbdevhw"
[ 20.233] (II) Loading sub module "vbe"
[ 20.233] (II) LoadModule: "vbe"
[ 20.233] (II) Loading /usr/lib/xorg/modules/libvbe.so
[ 20.276] (II) Module vbe: vendor="X.Org Foundation"
[ 20.276] compiled for 1.19.2, module version = 1.1.0
[ 20.276] ABI class: X.Org Video Driver, version 23.0
[ 20.276] (II) Loading sub module "int10"
[ 20.276] (II) LoadModule: "int10"
[ 20.276] (II) Loading /usr/lib/xorg/modules/libint10.so
[ 20.312] (II) Module int10: vendor="X.Org Foundation"
[ 20.312] compiled for 1.19.2, module version = 1.0.0
[ 20.312] ABI class: X.Org Video Driver, version 23.0
[ 20.312] (II) VESA(0): initializing int10
[ 20.323] (II) VESA(0): Primary V_BIOS segment is: 0xc000
[ 20.324] (II) VESA(0): VESA BIOS detected
[ 20.324] (II) VESA(0): VESA VBE Version 3.0
[ 20.324] (II) VESA(0): VESA VBE Total Mem: 65536 kB
[ 20.324] (II) VESA(0): VESA VBE OEM: VIA KM400
[ 20.324] (II) VESA(0): VESA VBE OEM Software Rev: 1.0
[ 20.324] (II) VESA(0): VESA VBE OEM Vendor:
[ 20.324] (II) VESA(0): VESA VBE OEM Product:
[ 20.324] (II) VESA(0): VESA VBE OEM Product Rev:
[ 20.353] (II) VESA(0): Creating default Display subsection in Screen section
"Default Screen Section" for depth/fbbpp 24/32
[ 20.353] (==) VESA(0): Depth 24, (--) framebuffer bpp 32
[ 20.353] (==) VESA(0): RGB weight 888
[ 20.353] (==) VESA(0): Default visual is TrueColor
[ 20.353] (==) VESA(0): Using gamma correction (1.0, 1.0, 1.0)
[ 20.353] (II) Loading sub module "ddc"
[ 20.353] (II) LoadModule: "ddc"
[ 20.353] (II) Module "ddc" already built-in
[ 20.353] (II) VESA(0): VESA VBE DDC supported
[ 20.353] (II) VESA(0): VESA VBE DDC Level 2
[ 20.353] (II) VESA(0): VESA VBE DDC transfer in appr. 1 sec.
[ 20.957] (II) VESA(0): VESA VBE DDC read successfully
[ 20.957] (II) VESA(0): Manufacturer: SAM Model: 8a2 Serial#: 808596534
[ 20.957] (II) VESA(0): Year: 2012 Week: 36
[ 20.957] (II) VESA(0): EDID Version: 1.3
[ 20.957] (II) VESA(0): Analog Display Input, Input Voltage Level: 0.700/0.300 V
[ 20.957] (II) VESA(0): Sync: Separate Composite SyncOnGreen
[ 20.957] (II) VESA(0): Max Image Size [cm]: horiz.: 41 vert.: 23
[ 20.957] (II) VESA(0): Gamma: 2.20
[ 20.957] (II) VESA(0): DPMS capabilities: Off; RGB/Color Display
[ 20.957] (II) VESA(0): First detailed timing is preferred mode
[ 20.957] (II) VESA(0): redX: 0.634 redY: 0.351 greenX: 0.334 greenY: 0.605
[ 20.957] (II) VESA(0): blueX: 0.146 blueY: 0.059 whiteX: 0.312 whiteY: 0.329
[ 20.957] (II) VESA(0): Supported established timings:
[ 20.957] (II) VESA(0): 720x400@70Hz
[ 20.957] (II) VESA(0): 640x480@60Hz
[ 20.957] (II) VESA(0): 640x480@67Hz
[ 20.957] (II) VESA(0): 640x480@72Hz
[ 20.957] (II) VESA(0): 640x480@75Hz
[ 20.957] (II) VESA(0): 800x600@56Hz
[ 20.957] (II) VESA(0): 800x600@60Hz
[ 20.957] (II) VESA(0): 800x600@72Hz
[ 20.957] (II) VESA(0): 800x600@75Hz
[ 20.957] (II) VESA(0): 832x624@75Hz
[ 20.957] (II) VESA(0): 1024x768@60Hz
[ 20.957] (II) VESA(0): 1024x768@70Hz
[ 20.958] (II) VESA(0): 1024x768@75Hz
[ 20.958] (II) VESA(0): Manufacturer's mask: 0
[ 20.958] (II) VESA(0): Supported standard timings:
[ 20.958] (II) VESA(0): #0: hsize: 1280 vsize 720 refresh: 60 vid: 49281
[ 20.958] (II) VESA(0): Supported detailed timing:
[ 20.958] (II) VESA(0): clock: 85.5 MHz Image Size: 410 x 230 mm
[ 20.958] (II) VESA(0): h_active: 1366 h_sync: 1436 h_sync_end 1579 h_blank_end 1792 h_border: 0
[ 20.958] (II) VESA(0): v_active: 768 v_sync: 771 v_sync_end 774 v_blanking: 798 v_border: 0
[ 20.958] (II) VESA(0): Ranges: V min: 56 V max: 75 Hz, H min: 30 H max: 81 kHz, PixClock max 95 MHz
[ 20.958] (II) VESA(0): Monitor name: S19B150
[ 20.958] (II) VESA(0): Serial No: H4MC902692
[ 20.958] (II) VESA(0): EDID (in hex):
[ 20.958] (II) VESA(0): 00ffffffffffff004c2da20836343230
[ 20.958] (II) VESA(0): 241601030e2917782a7841a259559b25
[ 20.958] (II) VESA(0): 0f5054bfee0081c00101010101010101
[ 20.958] (II) VESA(0): 010101010101662156aa51001e30468f
[ 20.958] (II) VESA(0): 33009ae61000001e000000fd00384b1e
[ 20.958] (II) VESA(0): 5109000a202020202020000000fc0053
[ 20.958] (II) VESA(0): 3139423135300a2020202020000000ff
[ 20.958] (II) VESA(0): 0048344d433930323639320a20200007
[ 20.958] (II) VESA(0): EDID vendor "SAM", prod id 2210
[ 20.958] (II) VESA(0): Using EDID range info for horizontal sync
[ 20.958] (II) VESA(0): Using EDID range info for vertical refresh
[ 20.958] (II) VESA(0): Printing DDC gathered Modelines:
[ 20.958] (II) VESA(0): Modeline "1366x768"x0.0 85.50 1366 1436 1579 1792 768 771 774 798 +hsync +vsync (47.7 kHz eP)
[ 20.958] (II) VESA(0): Modeline "800x600"x0.0 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e)
[ 20.959] (II) VESA(0): Modeline "800x600"x0.0 36.00 800 824 896 1024 600 601 603 625 +hsync +vsync (35.2 kHz e)
[ 20.959] (II) VESA(0): Modeline "640x480"x0.0 31.50 640 656 720 840 480 481 484 500 -hsync -vsync (37.5 kHz e)
[ 20.959] (II) VESA(0): Modeline "640x480"x0.0 31.50 640 664 704 832 480 489 492 520 -hsync -vsync (37.9 kHz e)
[ 20.959] (II) VESA(0): Modeline "640x480"x0.0 30.24 640 704 768 864 480 483 486 525 -hsync -vsync (35.0 kHz e)
[ 20.959] (II) VESA(0): Modeline "640x480"x0.0 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz e)
[ 20.959] (II) VESA(0): Modeline "720x400"x0.0 28.32 720 738 846 900 400 412 414 449 -hsync +vsync (31.5 kHz e)
[ 20.959] (II) VESA(0): Modeline "1024x768"x0.0 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync (60.0 kHz e)
[ 20.959] (II) VESA(0): Modeline "1024x768"x0.0 75.00 1024 1048 1184 1328 768 771 777 806 -hsync -vsync (56.5 kHz e)
[ 20.959] (II) VESA(0): Modeline "1024x768"x0.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz e)
[ 20.959] (II) VESA(0): Modeline "832x624"x0.0 57.28 832 864 928 1152 624 625 628 667 -hsync -vsync (49.7 kHz e)
[ 20.959] (II) VESA(0): Modeline "800x600"x0.0 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync (46.9 kHz e)
[ 20.959] (II) VESA(0): Modeline "800x600"x0.0 50.00 800 856 976 1040 600 637 643 666 +hsync +vsync (48.1 kHz e)
[ 20.959] (II) VESA(0): Modeline "1280x720"x60.0 74.48 1280 1336 1472 1664 720 721 724 746 -hsync +vsync (44.8 kHz e)
Voici aussi le Xorg.conf que j’ai généré :
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
ModulePath "/usr/lib/xorg/modules"
FontPath "/usr/share/fonts/X11/misc"
FontPath "/usr/share/fonts/X11/cyrillic"
FontPath "/usr/share/fonts/X11/100dpi/:unscaled"
FontPath "/usr/share/fonts/X11/75dpi/:unscaled"
FontPath "/usr/share/fonts/X11/Type1"
FontPath "/usr/share/fonts/X11/100dpi"
FontPath "/usr/share/fonts/X11/75dpi"
FontPath "built-ins"
EndSection
Section "Module"
Load "glx"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5 6 7"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "SWcursor" # [<bool>]
#Option "kmsdev" # <str>
#Option "ShadowFB" # [<bool>]
#Option "AccelMethod" # <str>
#Option "PageFlip" # [<bool>]
#Option "ZaphodHeads" # <str>
#Option "DoubleShadow" # [<bool>]
Identifier "Card0"
Driver "modesetting"
BusID "PCI:1:0:0"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
SubSection "Display"
Viewport 0 0
Depth 1
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 4
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 8
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 15
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 16
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
En espérant que tout cela vous aide à m’aider
Finalement, petite recherche sur le ouèbe et installation du bon paquet : https://packages.debian.org/stretch/xserver-xorg-video-openchrome qui est tout bêtement le pilote de la puce graphique VIA (du Radeon dans mes rêves et rien que dans mes rêves…).
“Là… ça marche” comme disait Jérémy Iron…
Merci à tous pour votre aide !