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author | marha <marha@users.sourceforge.net> | 2009-06-28 22:07:26 +0000 |
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committer | marha <marha@users.sourceforge.net> | 2009-06-28 22:07:26 +0000 |
commit | 3562e78743202e43aec8727005182a2558117eca (patch) | |
tree | 8f9113a77d12470c5c851a2a8e4cb02e89df7d43 /xorg-server/hw/xfree86/ddc/DDC.HOWTO | |
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Checked in the following released items:
xkeyboard-config-1.4.tar.gz
ttf-bitstream-vera-1.10.tar.gz
font-alias-1.0.1.tar.gz
font-sun-misc-1.0.0.tar.gz
font-sun-misc-1.0.0.tar.gz
font-sony-misc-1.0.0.tar.gz
font-schumacher-misc-1.0.0.tar.gz
font-mutt-misc-1.0.0.tar.gz
font-misc-misc-1.0.0.tar.gz
font-misc-meltho-1.0.0.tar.gz
font-micro-misc-1.0.0.tar.gz
font-jis-misc-1.0.0.tar.gz
font-isas-misc-1.0.0.tar.gz
font-dec-misc-1.0.0.tar.gz
font-daewoo-misc-1.0.0.tar.gz
font-cursor-misc-1.0.0.tar.gz
font-arabic-misc-1.0.0.tar.gz
font-winitzki-cyrillic-1.0.0.tar.gz
font-misc-cyrillic-1.0.0.tar.gz
font-cronyx-cyrillic-1.0.0.tar.gz
font-screen-cyrillic-1.0.1.tar.gz
font-xfree86-type1-1.0.1.tar.gz
font-adobe-utopia-type1-1.0.1.tar.gz
font-ibm-type1-1.0.0.tar.gz
font-bitstream-type1-1.0.0.tar.gz
font-bitstream-speedo-1.0.0.tar.gz
font-bh-ttf-1.0.0.tar.gz
font-bh-type1-1.0.0.tar.gz
font-bitstream-100dpi-1.0.0.tar.gz
font-bh-lucidatypewriter-100dpi-1.0.0.tar.gz
font-bh-100dpi-1.0.0.tar.gz
font-adobe-utopia-100dpi-1.0.1.tar.gz
font-adobe-100dpi-1.0.0.tar.gz
font-util-1.0.1.tar.gz
font-bitstream-75dpi-1.0.0.tar.gz
font-bh-lucidatypewriter-75dpi-1.0.0.tar.gz
font-adobe-utopia-75dpi-1.0.1.tar.gz
font-bh-75dpi-1.0.0.tar.gz
bdftopcf-1.0.1.tar.gz
font-adobe-75dpi-1.0.0.tar.gz
mkfontscale-1.0.6.tar.gz
openssl-0.9.8k.tar.gz
bigreqsproto-1.0.2.tar.gz
xtrans-1.2.2.tar.gz
resourceproto-1.0.2.tar.gz
inputproto-1.4.4.tar.gz
compositeproto-0.4.tar.gz
damageproto-1.1.0.tar.gz
zlib-1.2.3.tar.gz
xkbcomp-1.0.5.tar.gz
freetype-2.3.9.tar.gz
pthreads-w32-2-8-0-release.tar.gz
pixman-0.12.0.tar.gz
kbproto-1.0.3.tar.gz
evieext-1.0.2.tar.gz
fixesproto-4.0.tar.gz
recordproto-1.13.2.tar.gz
randrproto-1.2.2.tar.gz
scrnsaverproto-1.1.0.tar.gz
renderproto-0.9.3.tar.gz
xcmiscproto-1.1.2.tar.gz
fontsproto-2.0.2.tar.gz
xextproto-7.0.3.tar.gz
xproto-7.0.14.tar.gz
libXdmcp-1.0.2.tar.gz
libxkbfile-1.0.5.tar.gz
libfontenc-1.0.4.tar.gz
libXfont-1.3.4.tar.gz
libX11-1.1.5.tar.gz
libXau-1.0.4.tar.gz
libxcb-1.1.tar.gz
xorg-server-1.5.3.tar.gz
Diffstat (limited to 'xorg-server/hw/xfree86/ddc/DDC.HOWTO')
-rw-r--r-- | xorg-server/hw/xfree86/ddc/DDC.HOWTO | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/xorg-server/hw/xfree86/ddc/DDC.HOWTO b/xorg-server/hw/xfree86/ddc/DDC.HOWTO new file mode 100644 index 000000000..833a7ab54 --- /dev/null +++ b/xorg-server/hw/xfree86/ddc/DDC.HOWTO @@ -0,0 +1,97 @@ + DDC.HOWTO + + This file describes how to add DDC support to a chipset driver. + +1) DDC INITIALIZATION + + When implementing DDC in the driver one has the choice between + DDC1 and DDC2. + DDC1 data is contiuously transmitted by a DDC1 capable display + device. The data is send serially over a data line; the Vsync + signal serves as clock. Only one EDID 1.x data block can be + transmitted using DDC1. Since transmission of an EDID1 block + using a regular Vsync frequency would take up several seconds + the driver can increase the Vsync frequency to up to 25 kHz as + soon as it detects DDC1 activety on the data line. + DDC2 data is transmitted using the I2C protocol. This requires + an additional clock line. DDC2 is capable of transmitting EDID1 + and EDID2 block as well as a VDIF block on display devices that + support these. + Display devices switch into the DDC2 mode as soon as they detect + activety on the DDC clock line. Once the are in DDC2 mode they + stop transmitting DDC1 signals until the next power cycle. + + Some graphics chipset configurations which are not capable of + DDC2 might still be able to read DDC1 data. Where available + DDC2 it is preferrable. + + All relevant prototypes and defines are in xf86DDC.h. + DDC2 additionally requires I2C support. The I2C prototypes + are in xf86i2c.h. + + DDC1 Support: + + The driver has to provide a read function which waits for the + end of the next Vsync signal and reads in and returns the status + of the DDC line: + + unsigned int XXX_ddc1Read(ScrnInfoPtr pScrn) + + Additionally a function is required to inclrease the Vsync + frequency to max. 25 kHz. + + void XXX_ddc1SetSpeed(ScrnInfoPtr pScrn, xf86ddcSpeed speed) + + If the speed argument is DDC_FAST the function should increase + the Vsync frequency on DDC_SLOW it should restore the original + value. For convenience a generic ddc1SetSpeed() function is provided + in the vga module for VGA-like chipsets. + + void vgaHWddc1SetSpeed(ScrnInfoPtr pScrn, sf86ddcSpeed speed). + + To read out the DDC1 data the driver should call + + xf86MonPtr xf86DoEDID_DDC1(int scrnIndex, + void (*DDC1SetSpeed)(ScrnInfoPtr, xf86ddcSpeed), + unsigned int (*DDC1Read)(ScrnInfoPtr)) + + in PreInit(). DDC1SetSpeed is a pointer to the SetSpeed() + function, DDC1Read has to point to the DDC1 read function. + The function will return a pointer to the xf86Monitor structure + which contains all information retreived by DDC. + NULL will be returned on failure. + + DDC2 Support + + To read out DDC2 information I2C has to be initialized first. + (See documentation for the i2c module). + The function + + xf86MonPtr xf86DoEDID_DDC2(int scrnIndex, I2CBusPtr pBus) + + is provided to read out and process DDC2 data. A pointer + to the I2CBusRec of the appropriate I2C Bus has to be passed + as the second argument. + The function will return a pointer to the xf86Monitor structure + which contains all information retreived by DDC. + NULL will be returned on failure. + + Printing monitor parameters + + To print out the information contained in the xf86Monitor + structure the function + + xf86MonPtr xf86PrintEDID(xf86MonPtr monitor) + + is provided. + + Further processing of the xf86Monitor structure is not yet + implemented. Howerver it is planned to use the information + about video modes, gamma values etc. + Therefore it is strongly recommended to read out DDC data + before any video mode processing is done. + + + + +$XFree86: xc/programs/Xserver/hw/xfree86/ddc/DDC.HOWTO,v 1.2 1998/12/06 13:30:39 dawes Exp $ |