Bug 9854

Summary: gx50: enable VID_PLL before trying to set its M/N/P values
Product: xorg Reporter: Tilman Sauerbeck <tilman>
Component: Driver/mgaAssignee: Xorg Project Team <xorg-team>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: alexdeucher, mephinet
Version: git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Patch none

Description Tilman Sauerbeck 2007-02-02 09:18:30 UTC 
This applies to g450/g550 only (AFAIK):

We currently set the M/N/P values for the video PLL before the video pll is actually powered up. This doesn't work, because VID_PLL_STAT will always say the PLL isn't locked if it's not powered up. Of course this doesn't work.

So the fix is to _first_ power up the video pll, and then setting its M/N/P values.

Symptoms:
"signal out of range" weirdness for CRTC2.
Comment 1 Tilman Sauerbeck 2007-02-02 23:48:02 UTC 
Note to self: this one probably only applies to g550, since dual-head is working with the current code on g450 (with two vga outputs). Maybe verify that g450 uses the video pll, too.
Comment 2 Daniel Stone 2007-02-27 01:36:08 UTC 
Sorry about the phenomenal bug spam, guys.  Adding xorg-team@ to the QA contact so bugs don't get lost in future.
Comment 3 mephinet 2007-03-01 12:17:50 UTC 
Hi,
what I am experiencing with my MGA G550 is that even though both screens get initalized to a correct refresh rate of 60 Hz:

(**) MGA(0): *Default mode "1280x1024": 108.0 MHz, 64.0 kHz, 60.0 Hz
(**) MGA(1): *Default mode "1280x1024": 108.0 MHz, 64.0 kHz, 60.0 Hz

the screen that is not connected to the DVI receives a 66Hz/71KHz signal instead, which it (being an LCD) cannot cope with.

Is this related to the incorrect setup of the PLL?
I'm running version 7.1.1 with the mga driver (no binary drivers).
Thanks!
Comment 4 Tilman Sauerbeck 2007-03-04 22:57:00 UTC 
mephinet,
this bug isn't about wrong setup of the VID_PLL values in general ;)
Please file a separate bug for your problem. I'm not sure if it's due to the video PLL though.
Comment 5 Tilman Sauerbeck 2007-03-04 22:58:24 UTC 
Created attachment 8977 [details] [review]
Patch

This patch fixes the problem on my G550 dual-dvi. It's pretty damn ugly, and we can fix it in a nicer way in the randr-1.2 branch eventually, so don't commit this please.
Comment 6 Tilman Sauerbeck 2007-03-18 04:04:07 UTC 
Fixed in the randr-1.2 branch.

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