[SOLVED] xrandr and radeonsi. underscan not working

[kon14]

So my tv monitor display (Sony KDL-26L4000) turns out to force overscan through hdmi. There's no dvi port and no setting for turning it off or using a full pixel mode.
I'm using radeon (radeonsi) and have also included the appropriate blobs for my card in the kernel. More on that later.

I've searched everywhere, downloaded the manual, tried the service menu, triple-checked everything... there's just no option for it and no firmware update to fix this.
Apart from having a whole lot of overscan, there's also image corruption or whatever you want to call that.
There was no 60hz option for 1920x1080 by default and creating a mode for it using cvt/gtf and xrandr just gives me a black display (there's no other issue with xrandr, just the 60hz thingy).

Here's a screenshot with 1920x1080 @30hz through hdmi: http://i.imgur.com/YPnsWXc.png
Note that the image corruption doesn't get captured... I'd describe it as splitting the image in vertical lines and having some deviation for half of them.

I've tried to solve the overscan issue by using xrandr's underscan, but it just won't work (makes no visible difference. doesn't even refresh/reload the mode) for the 1920x1080 resolution and will only mess with my 1360x1080 one after I revert back to it.
I also made sure the underscan option was on, tried vborder/hborder, panning, scaling and even transforming. The only thing that seemed to change anything at all was --transform, but I remember it only working for 1360x1080 as well :S.

For the sake of testing I tried downgrading to analog using vga with a dvi to vga adapter (my card: Radeon HD7950 doesn't have a vga port). I believe a real 15cable vga supports 1920x1080, right?
Didn't work out either. The issue is NOT distro specific or computer specific, it wouldn't work when I had a debian installation and it won't work with my gentoo laptop (also through hdmi +radeon driveri), but it would work when using catalyst's underscan scaling scrollbar in amdcccle.

Fixing the resolution was the main reason why I used to use fglrx. I've been trying radeonsi periodically and, other than this annoying issue, it seems to be working like a charm. I'm tired of catalyst's bugs and don't plan on reverting back to it so I guess I've have to face this.

Here's my xrandr:
Screen 0: minimum 320 x 200, current 1360 x 768, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected 1360x768+0+0 (normal left inverted right x axis y axis) 1600mm x 900mm
1360x768 60.0*+
1920x1080i 60.1 50.0 60.0
1280x720 60.0 50.0 59.9
1440x576i 50.1
1024x768 60.0
1440x480i 60.1 60.1
800x600 60.3
720x576 50.0
720x480 60.0 59.9
640x480 60.0 59.9
....more display ports

I believe I mentioned everything there is, but I'll add anything that I might have forgotten below.
Edit: I should also mention that trying to force 60hz using a mode from cvt or gtf just gives me the blacks...

[Ant P.]

I've had problems like this with my off-brand TV's HDMI, here's a few things you could try:

* Boot with "radeon.audio=0" and see if that changes things. For some reason having that enabled forces overscan on for me.
* Have you tried cvt with the -r flag?
* Is your screen actually 1920x1080, or is it a 1360x768 panel with a lying EDID?

[kon14]

I'll the radeon.audio=0 a shot. That's a kernel parameter right?
I haven't tried any options for cvt. I'll do so.
I have a 1920x1080i capable tv monitor from sony.

One more thing I remember trying was using --set audio force-dvi which produces no more results for me.
I'll try the above and update after rebooting.

[kon14]

I want to ultra thank you for that little -r in cvt . I suspected the modeline, but had no clue about the existence of such an option at all.
After trying a reduced modeline I was greeted with a zoomed version of what looked like to be a zormal, non corrupted display. Even more, I was capable of adjusting the underscan of xrandr!