> > For DAC mode P2 should be from 5 to 10 > > For LVDS mode P2 can be from 7 to 12 > > > > All other values seem to match what we have. > > > > Since the driver has a number of TODO's about LVDS support perhaps a > > better range would be 7 to 10 which should work for both? > > > > Your thoughts appreciated? > > Ok annoyingly the driver seems to ignore p2 from the table and > overwrite with a different set of constants which are 7 to 14 > presumably it is trying to handle LVDS mode. > > The driver also seems to have several different ways of detecting LVDS > mode, hmm. For LVDS mode P2 is 7 or 14. Here is the Xorg driver which Haiku is based off. Look through the tree. http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/ You'll see Xorg uses 7 & 14 for LVDS P2 here: http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/tree/src/i830_display.c?id=5257e36f502676fd6a44bbb8e747d9138ed3bc5c#n116 The pdf link you gave also had the same info, I quote below: FPB0/FPB1 P2 Clock Divide: For DPLLB in Serial DVO or DAC mode , BITS(27:26)=01 00 = Divide by 10. This is used when Dot Clock =< 270MHz in sDVO, HDMI, or DAC modes 01 = Divide by 5. This is used when Dot Clock >270MHz 10 = Reserved 11 = Reserved For DPLLB in LVDS mode, BITS(27:26)=10 00 = Divide by 14. This is used in Single-Channel LVDS 01 = Divide by 7. This is used in Dual-Channel LVDS 10 = Reserved 11 = Reserved What is going on for me, siarzhuk ( & likely you & others ) is that: 1) Driver is trying to use DAC mode/p2 values 2) Our video cards want ( Single-Channel ) LVDS mode 3) Driver fails & hangs Look at the picture I've attached to the ticket. http://dev.haiku-os.org/attachment/ticket/3149/P1010003.JPG You'll see that P2 limits are 10 & 5 ( DAC ) but it found P2 = 14 ( LVDS ) for me the first time around. Then the driver tries to adjust the other values so that I can use DAC p2 = 10 which does not work - hangs. In general, the solution involves fixing LVDS mode & providing values of 14 & 7 for P2 when LVDS detected. Regards, _________________________________________________________________