Re: Twister savagefb doesn't sync (resolved for 640x480@64K)

["Alex Deucher" <alexdeucher@gmail.com>]

On 6/11/06, Vassilis Virvilis <vasvir@iit.demokritos.gr> wrote:
> Hi Alex,
>
> I would like to thank you and Antonino for all the help so far. I have finally
> manage to make my twister to sync with both of my screens (one TFT, one CRT).
>
> I am attaching the patch. The patch itself disables all modes other than
> 640x480@64K-60Hz. Note that the patch is clearly inapropriate but it
> may sparkle some discussion about how this thing works.
>
> One more question:
>
> Alex Deucher wrote:
> >> > The reason the savage xorg drver uses the bios is because almost every
> >> > panel they connect to the chip seems to require fairly custom timings.
> >> > the twisters and prosavages are even worse than the discrete chips.
> >> > Also, only the bios seems to know the magic incantation necessary for
> >> > dualhead.  I tried for a while to add non-bios mode setting to crtc2
> >> > without much luck.
> >>
>
> When you say panel what do you mean?
> a) The rest of the framebuffer and scan logic resided in CRTC?
> b) The screen attached to CRTC?
>
> I believe a) but I would like to know for sure.

I'm not sure I understand your question.  The panel connects to the
chip via a built in flat panel interface, however it has to be driven
with timings and a clock just like a CRT.  The CRTC can drive either
the FP interface or the DAC or both.  Based on you patch it seems you
only need to tweak the clock.  Perhaps if we had a few more testers we
could figure out a pattern for common panels and put in some sort of
generic fix.

Alex

>
> Thanks again...
>
>     .bill
>
>
>