Re: More questions and patches for 835GM/ns2501 DVO

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Hi Daniel,
I also tried a lot with the two-monitor case and again went deeply into the
DPLL setup logic.
The differences I observed before are simply due to the initial resolution
(800x600), in the final
resolution, the DPLL settings are actually correct. What I get there is:
I suspect that due to the pipe A quirk logic we actually get the setup
sequence for the DPLLs completely wrong. This will require a bit more
magic to make it work correctly ... But I have some ideas.
-Daniel
Well, maybe. The register contents that are listed in my mail are read out from the hardware exactly when the DVO gets stuck, actually right before it. From what I can see from there is that the PLL setup and DVO setup look actually ok (from what I can tell). What is also remarkable is that the DVO-reenable logic does succeed by writing the same value to the DPLL_A and DPLL_B registers, which is the proper value for a 1024x768 screen. However, the DPLL_B register value is correct, whereas the DPLL_A register contains values that are likely useful for the VGA
output.

Now, here is the miracle: The DVOC register indicates that the DVO gets its input from pipe B. However, writing the correct value into DPLL_A (!) (remember, DPLL_B is already set correctly) revives the DVO.

Thus, I wonder how this can be. The only explanation I have is that the DVO is still fed by pipe A, and not by pipe B. Maybe there is something else that needs to be done to switch the DVO to pipe B.

Anyhow, happy to take your ideas. Unfortunately, I will again not have this specific laptop available for some while. I do have an R31 for testing, though its display is connected via LVDS and not via a DVO. The chipset seems to be similar otherwise, though.

Greetings,
    Thomas

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