[haiku-development] Re: Asus Eee PC B202
- From: Nick <tonestone57@xxxxxxxxxxx>
- To: <haiku-development@xxxxxxxxxxxxx>
- Date: Sun, 15 Feb 2009 11:12:46 -0700
> > 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,
_________________________________________________________________
Other related posts:
