xref: /xsrc/external/mit/xf86-video-geode/dist/README

xf86-video-geode -- AMD Geode GX and LX graphics driver for X.org
=================================================================
README last updated: 2020-12-15

1.INTRODUCTION

This is the X graphics driver for the AMD Geode GX and LX processors.
The GX component supports both XAA and EXA for graphics acceleration.
The LX component supports EXA, including compositing. Both support Xv 
overlay and dynamic rotation with XRandR. Additionally, a V4L2 driver
for the LX's video input port (VIP) feature is provided as "ztv".

2.DEPENDENCIES

Since version 2.9.0, this driver depends on X server 1.3 or greater,
because it utilizes the new common DDC probing libraries from X.Org.

3.ROADMAP

Support for old GX1 Geodes by Cyrix and NSC will be reintroduced soon,
at which point xf86-video-cyrix and xf86-video-nsc will be retired.

Until then, the current situation for Geode coverage is as follow:
 
xf86-video-geode
 * Geode LX      (a.k.a. GX3) PCI ID 0x1022:0x2081
 * Geode GX      (a.k.a. GX2) PCI ID 0x100B:0x0030 (re-branded GX2)

xf86-video-nsc
 * Geode GX2     (a.k.a. GX2) PCI ID 0x100B:0x0030 (a.k.a. "Red Cloud")
 * Geode SCx200  (a.k.a. GX1) PCI ID 0x100B:0x0504 
 * Geode SC1400  (a.k.a. GX1) PCI ID 0x100B:0x0104 

xf86-video-cyrix
 * Geode MediaGX (a.k.a. GX1) PCI ID 0x1078:0x0104 

Please note that both NSC and GEODE support GX2. This is indeed correct.
However, only GEODE has up-to-date code, while NSC is deprecated. 

4.MAXIMUM RESOLUTIONS

The driver supports all maximum resolutions advertised by AMD, namely:

LX: 1920x1440 (CRT) and 1600x1200 (TFT)
GX: 1600x1200 (CRT) and 1280x1024 (TFT)
SC: 1280x1024 (CRT/TFT) *** Currently unsupported by this driver ***

Additionally, on the LX, the driver can DCC probe the display and calculate
the clockrate for the maximum resolution supported by the display. However,
this won't work on LX platforms with GPIO configured for serial console. On
such hardware, the resolution must be specified in /etc/X11/xorg.conf.

5.CONFIGURATION OPTIONS

You can specify driver options in /etc/X11/xorg.conf in the usual fashion:

Section "Device"
	Identifier "AMD Geode"
	Driver "geode"
	Option "OptionName" "value"
	...
EndSection

The following options may be added to such a Device section:

5.1.COMMON OPTIONS

FBSize: Specify the size of the video space (in bytes)
NoAccel: Disable hardware assisted acceleration
NoCompression: Disable video bandwidth compression
NoPanel: Disable panel support
Rotate: Select an initial orientation - LEFT, INVERT, CCW
SWCursor: Enable software cursors (essentially disabling HW cursor support)

5.2.GX-SPECIFIC OPTIONS

AccelMethod: "XAA" (default) or "EXA"
PanelGeometry: Specify the geometry of the attached panel ("<width>x<height>")
OSMImageBuffers: Set the number of image buffers (XAA only)
OSMColorExpBuffers: Set the number of color expansion buffers (XAA only)

5.3.LX-SPECIFIC OPTIONS

ExaScratch: Specify the amount of extra EXA scratch buffer (in bytes)

6.FREQUENTLY ASKED QUESTIONS (FAQ)

Q: Why doesn't the GEODE driver work on recent Linux kernels?

A: Since kernel 4.x Linux has strong memory protection. If the kernel is
   booted with a frame buffer (e.g. vesafb) it reserves the video memory
   for itself. Disabling this requires booting the kernel in non-graphic
   mode. On GRUB, this is configured by this /etc/default/grub option:

   GRUB_GFXPAYLOAD_LINUX=text

   Alternately, adding iomem=relaxed to GRUB_CMDLINE_LINUX_DEFAULT will
   allow the video memory to be accessed by vesafb and the GEODE driver.

   Once either option has been added and the GRUB configuration refreshed,
   the GEODE driver will launch on recent kernels as previously.

Q: Why doesn't the GEODE driver work at WXGA (wide screen) resolutions?

A: Make sure that TFT Panel support is disabled in the BIOS settings, 
   otherwise resolutions will be restricted to traditional VGA modes. 
   The GEODE offers a choice between CRT-only, CRT+TFT, TFT-only for
   output device and selecting CRT-only removes the VGA restriction.

Q: How can these hardcoded modes be expanded to support a WXGA laptop?

A: By adding the desired modes to /etc/X11/xorg.conf as follow:

   1) Use either the "cvt" or "gtf" command to determine the modeline:

      cvt 1024 600 60

      Where 1024x600 is the resolution and 60 the refresh rate. 
      The resulting modeline using "gtf" is:

Modeline "1024x600" 48.96 1024 1064 1168 1312 600 601 604 622 -hsync +vsync

   2) Add it to the bottom of the "Monitor" section in /etc/X11/xorg.conf.
      In this example, we created entries for two modes and configured the
      larger resolution to be our preferred choice.

#############################################################
# /etc/X11/xorg.conf for 1024x600 and 800x480 laptop panels #
#############################################################
#### By J.KASPER and B.HIBRY #### for Hercules eCafe 800 ####
#############################################################
Section "Module"
    Load  "ztv"
EndSection
Section "Device"
    Identifier	"card0"
    Driver	"geode"
    BusID	"PCI:0:1:1"
    Option	"PanelMode" "33450 800 840 968 1056 480 490 492 525"
EndSection
Section "Monitor"
    Identifier	"monitor0"
    Modeline  "1024x768" 64.56 1024 1056 1296 1328 768 783 791 807 -hsync +vsync
    Modeline  "1024x600" 48.96 1024 1064 1168 1312 600 601 604 622 -hsync +vsync
    Modeline   "800x480" 33.45  800  840  968 1056 480 490 492 525 -hsync +vsync
    Option	"dpms"
EndSection
Section "Screen"
    Identifier	"Default Screen"
    Monitor	"monitor0"
    Device	"card0"
    DefaultDepth 24
    Subsection "Display"
        Depth 24
        Modes "1024x600" "1024x768" "800x480"
    EndSubsection        
EndSection
### EOF ###

Q: Why doesn't screen rotation work?

A: Make sure that a sufficient amount of video RAM is reserved in the BIOS,
   otherwise rotation will fail and this error message appear in Xorg.log:

      Couldn't allocate the shadow memory for rotation
      You need XX bytes, but only YY bytes are available

Q: How do I produce useful information whenever submitting a bug report?

A: See https://www.x.org/wiki/Development/Documentation/ServerDebugging
   and follow the instructions found there.

Q: How do I test development snapshots from the upstream GIT repository?

A: Run the following commands from a command line interpreter shell:
   1. git clone git://anongit.freedesktop.org/git/xorg/driver/xf86-video-geode 
   2. Debian/Ubuntu:  apt-get install autoconf automake libtool xutils-dev
                      apt-get install build-dep xserver-xorg-video-geode
     Fedora/Red Hat:  yum install autoconf automake libtool xorg-x11-util-macros
                      yum-builddep xorg-x11-drv-geode
   3. cd xf86-video-geode
   4. ./autogen.sh
   5. make distcheck
   ...then install the driver manually.

Q: What is the preferred method for submitting patches to this driver?

A: See https://www.x.org/wiki/Development/Documentation/SubmittingPatches
   and submit the patches to the Geode X.org mailing list or to gitlab
   in the xf86-video-geode project.

7.PROJECT CONTACTS

Project homepage:
https://www.x.org/wiki/GeodeDriver

Mailing list:
https://lists.x.org/mailman/listinfo/xorg-driver-geode

Bug reports:
https://gitlab.freedesktop.org/xorg/driver/xf86-video-geode/issues

Code repository:
https://gitlab.freedesktop.org/xorg/driver/xf86-video-geode

IRC channel:
#geode on the Freenode network.

.EOF.