I'll try to summarize.
The OVRACT register controls how the overlay lines up with the TV/LCD
output.
This alignment needs to be calculated based on the horizontal timings being
used on the TV.
On an i810/i815 the video bios will program the timings for the TV
controller
if it is used as the primary output device. The CRT timings are then
centered
in the TV timings which allows XFree to display on the TV using one, fixed,
TV resolution that was chosen by the vbios.
Since this mechanism was designed for compatibility with VGA, DOS etc, the
vbios is not programming the OVRACT register... this register was being set
in Set Mode which made it work for at least one TV controller in at least
one mode.
If we base the OVRACT register programming on the sync timings set by the
vbios you can probably make it work for everyone.
If the TV is active:
Regs 0x60000-0x60023 control the timings in use by the GMCH is bit 28
in lcdtv_c is 0 (This is usually the case). The CRTC timings are
centered in these values if bit 29 is 1 (usual case)
OVRACT needs to be programmed off the TV regs if they are in use.
If the TV is not active
CRTC regs control the timings
OVRACT needs to be programmed off the CRTC regs
For an LCD the vbios may or may not be using the LCD/TV timings depending
on the capabilities of the LCD device. I suggest checking bit 28 of
lcdtv_c to make sure that the TV regs are in use. The centering probably
doesn't matter because the end timings are still those in the TV regs.
At this point, if this works for both of you, I suggest committing it and
asking for lots of testing. You will have a lot of permutations of
LCD encoders, LCD displays, and TV encoders that may all behave
differently. Only widespread testing will indicate if it is an
improvement.
Egbert,
Wherever you end up putting this you can probably replace any other
programming of OVRACT. Just make sure that if you switch away or change
modes for any reason that you read the timings again. A stand alone TV
driver could have changed them.
-Matt
File : xc/programs/Xserver/hw/xfree86/drivers/i810/i810_driver.c
Somewhere near line 1522
unsigned int lcdtv_c=0;
unsigned int tv_htotal=0;
/* OVRACT Register */
lcdtv_c = INREG(0x60018);
tv_htotal = INREG(0x60000);
if((lcdtv_c & 0x80000000) &&
(~lcdtv_c & 0x20000000) &&
(tv_htotal)) {
i810Reg->OverlayActiveStart = (temp>>16) - 31;
i810Reg->OverlayActiveEnd = (temp & 0x3ff) - 31;
} else {
i810Reg->OverlayActiveStart = mode->CrtcHTotal - 32;
i810Reg->OverlayActiveEnd = mode->CrtcHDisplay - 32;
}
-----Original Message-----
From: Egbert Eich [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, October 16, 2002 5:44 AM
To: [EMAIL PROTECTED]
Cc: Sebastien BASTARD
Subject: RE: [Xpert]!! Correction for i810 driver !!
Hi Matthew,
thanks for following up on this.
Sottek, Matthew J writes:
> Egbert,
> Actually... I'm thinking there is a problem with this way too. We need
> another "if" in there. i.e.
>
> if((tv is on) && (vbios left a set of TV timings for us)) {
> use TV regs;
> } else {
> use crt regs;
> }
>
> Otherwise we might end up using the TV timings even when the display is
not
> on
> the TV (depending on what the vbios does when using CRT in a system that
has
> a TV controller).
Yes, I suspected something like this.
>
> Check the LCDTV_C register (offset 0x60018) bit 31. If it is set then
> the TV is in use. So try this one:
>
> File : xc/programs/Xserver/hw/xfree86/drivers/i810/i810_driver.c
> Somewhere near line 1522
>
>
> unsigned int lcdtv_c=0;
> unsigned int tv_htotal=0;
>
> /* OVRACT Register */
> lcdtv_c = INREG(0x60018);
> tv_htotal = INREG(0x60000);
>
> if((lcdtv_c & 0x80000000) && (tv_htotal)) {
> i810Reg->OverlayActiveStart = (temp>>16) - 31;
> i810Reg->OverlayActiveEnd = (temp & 0x3ff) - 31;
> } else {
> i810Reg->OverlayActiveStart = mode->CrtcHTotal - 32;
> i810Reg->OverlayActiveEnd = mode->CrtcHDisplay - 32;
> }
>
>
We may need more changes than that.
It is still not clear to me if the change in
the OverlayActiveStart and OverlayActiveEnd settings
will do on an LCD.
In the end we are just reducing the ActiveStart and
ActiveEnd registers by 31. I don't see why we need to
do this.
Also we read out the values in SetMode. When this function
gets called the values of these regsiters may not be the
original ones set by the BIOS any more as SetMode()
may be called several times.
We need to grab the value in PreInit() - or if the
BIOS may change them behind our back - save and compare
the value we have set and refresh it in case it has
changed.
However I won't implement this until I understand better
why we have to touch these values in the first place.
Sebastien, could you please check what happens when these
these values are left the way the BIOS set them?
Regards,
Egbert.
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