Thanks both for the answers. The driver would still be on https://archlinux.org/packages/community/x86_ … /unichrome-dri/ ArchLinux files and seems was updated until 2018.
The Xorg 2D driver I loaded instead is this one still on the ubuntu sources:
[ 56.624] (II) LoadModule: "openchrome"
[ 56.667] (II) Loading /usr/lib/xorg/modules/drivers/openchrome_drv.so
[ 56.788] (II) Module openchrome: vendor="https://www.freedesktop.org/wiki/Openchrome/"
[ 56.788] compiled for 1.19.5, module version = 0.6.0
[ 56.788] Module class: X.Org Video Driver
[ 56.788] ABI class: X.Org Video Driver, version 23.0
[ 56.788] (II) LoadModule: "modesetting"
[ 56.788] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[ 56.944] (II) Module modesetting: vendor="X.Org Foundation"
[ 56.944] compiled for 1.19.6, module version = 1.19.6
[ 56.944] Module class: X.Org Video Driver
[ 56.944] ABI class: X.Org Video Driver, version 23.0
[ 56.944] (II) LoadModule: "fbdev"
[ 56.945] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[ 57.077] (II) Module fbdev: vendor="X.Org Foundation"
[ 57.078] compiled for 1.19.3, module version = 0.4.4
[ 57.078] Module class: X.Org Video Driver
[ 57.078] ABI class: X.Org Video Driver, version 23.0
[ 57.078] (II) LoadModule: "vesa"
[ 57.078] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
[ 57.175] (II) Module vesa: vendor="X.Org Foundation"
[ 57.175] compiled for 1.19.3, module version = 2.3.4
[ 57.175] Module class: X.Org Video Driver
[ 57.175] ABI class: X.Org Video Driver, version 23.0
[ 57.175] (II) OPENCHROME: Driver for VIA Chrome chipsets: CLE266,
KM400 / KM400A / KN400 / P4M800, K8M800 / K8N800,
PM800 / PN800 / PM880 / CN333 / CN400, P4M800 Pro / VN800 / CN700,
CX700 / VX700, P4M890 / VN890 / CN800, K8M890 / K8N890,
P4M900 / VN896 / CN896, VX800 / VX820, VX855 / VX875, VX900
[ 57.175] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[ 57.175] (II) FBDEV: driver for framebuffer: fbdev
[ 57.175] (II) VESA: driver for VESA chipsets: vesa
[ 57.223] (!!) VIA Technologies does not support this driver in any way.
[ 57.223] (!!) For support, please refer to https://www.freedesktop.org/wiki/Openchrome/.
[ 57.223] (!!) (openchrome 0.6.0 release)
[ 57.223] (WW) Falling back to old probe method for modesetting
[ 57.224] (EE) open /dev/dri/card0: No such file or directory
[ 57.224] (WW) Falling back to old probe method for fbdev
[ 57.224] (II) Loading sub module "fbdevhw"
[ 57.224] (II) LoadModule: "fbdevhw"
[ 57.224] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 57.258] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 57.258] compiled for 1.19.6, module version = 0.0.2
[ 57.258] ABI class: X.Org Video Driver, version 23.0
[ 57.258] (WW) Falling back to old probe method for vesa
[ 57.259] (II) CHROME(0): viaPreInit
[ 57.259] (II) CHROME(0): VIAGetRec
[ 57.259] (--) CHROME(0): Chipset: P4M890 / VN890 / CN800
[ 57.259] (--) CHROME(0): Chipset revision: 0
[ 57.459] (EE) CHROME(0): [drm] Failed to open DRM device for pci:0000:01:00.0: No such file or directory
[ 57.524] (II) Loading sub module "vgahw"
[ 57.524] (II) LoadModule: "vgahw"
[ 57.524] (II) Loading /usr/lib/xorg/modules/libvgahw.so
[ 57.559] (II) Module vgahw: vendor="X.Org Foundation"
[ 57.559] compiled for 1.19.6, module version = 0.1.0
[ 57.559] ABI class: X.Org Video Driver, version 23.0
[ 57.559] (--) CHROME(0): Probed amount of VideoRAM = 65536 kB
[ 57.559] (II) CHROME(0): Entered viaMapMMIO.
[ 57.559] (--) CHROME(0): Mapping MMIO at address ... with size 52 KB.
[ 57.560] (--) CHROME(0): Mapping 2D Host BitBLT space at address .. with size 2048 KB.
[ 57.560] (--) CHROME(0): Mapping the frame buffer at address .. with size 65536 KB.
[ 57.560] (--) CHROME(0): Frame buffer start address: .., free start: 0x0 end: ..
[ 57.560] (II) CHROME(0): Entered viaMMIOEnable.
[ 57.560] (II) CHROME(0): Exiting viaMMIOEnable.
[ 57.560] (II) CHROME(0): vgaHWGetIOBase: hwp->IOBase is ..
[ 57.560] (II) CHROME(0): Exiting viaMapMMIO.
[ 57.560] (II) CHROME(0): Creating default Display subsection in Screen section
"Default Screen Section" for depth/fbbpp 24/32
[ 57.560] (==) CHROME(0): Depth 24, (--) framebuffer bpp 32
[ 57.560] (==) CHROME(0): RGB weight 888
[ 57.560] (==) CHROME(0): Default visual is TrueColor
[ 57.561] (II) CHROME(0): VIASetupDefaultOptions - Setting up default chipset options.
[ 57.561] (==) CHROME(0): Shadow framebuffer is disabled.
[ 57.561] (==) CHROME(0): Hardware acceleration is enabled.
[ 57.561] (==) CHROME(0): Using EXA acceleration architecture.
[ 57.561] (==) CHROME(0): EXA composite acceleration enabled.
[ 57.561] (==) CHROME(0): EXA scratch area size is 4096 kB.
[ 57.561] (==) CHROME(0): Using hardware two-color cursors and software full-color cursors.
[ 57.561] (==) CHROME(0): GPU virtual command queue will be enabled.
[ 57.561] (==) CHROME(0): DRI IRQ will be enabled if DRI is enabled.
[ 57.561] (==) CHROME(0): AGP DMA will be enabled if DRI is enabled.
[ 57.561] (==) CHROME(0): AGP DMA will be used for 2D acceleration.
[ 57.561] (==) CHROME(0): PCI DMA will not be used for XV image transfer if DRI is enabled.
[ 57.561] (==) CHROME(0): Xv Bandwidth check is enabled.
[ 57.561] (==) CHROME(0): Will not impose a limit on video RAM reserved for DRI.
[ 57.561] (==) CHROME(0): Will try to allocate 32768 kB of AGP memory.
[ 57.561] (==) CHROME(0): TV dotCrawl is disabled.
[ 57.561] (==) CHROME(0): TV deflicker is set to 0.
[ 57.561] (==) CHROME(0): No default TV type is set.
[ 57.561] (==) CHROME(0): No default TV output signal type is set.
[ 57.561] (==) CHROME(0): Will not print VGA registers.
[ 57.561] (==) CHROME(0): Will not scan I2C buses.
[ 57.561] (II) CHROME(0): Detected MemClk 7
[ 57.561] (II) CHROME(0): ViaGetMemoryBandwidth. Memory type: 7
But there're even some warning or errors..
[ 57.459] (EE) CHROME(0): [drm] Failed to open DRM device for pci:0000:01:00.0: No such file or directory
[ 58.407] (WW) CHROME(0): [XvMC] Cannot use XvMC without DRI!
[ 58.441] (EE) AIGLX: reverting to software rendering
I know it'd be much easier to switch to any other AMD card that has a good ready to use driver for any card after the Radeon, but I didn't find the Unichrome to be "that bad" in Windows ME all considered.. I got 4000 points on 3DMark2000 and rendering quality was quite good. I thought it could be a good retro igpu for old games. But I can't install obviously such old distributions. Maybe only archlinux still support that driver.