[Intel-gfx] Sandy Bridge Desktop - 1920x1080i interlace not working

[Daniel Vetter]

On Wed, Jan 25, 2012 at 02:00:37AM +0100, Alfonso Fiore wrote:
> On Sun, Jan 22, 2012 at 11:40 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> >
> > Actually I only need the output of intel_reg_dumper, resolution
> > doesn't really matter that much. It just needs to be a HDMI-only
> > configuration that works.
> 
> Hi Daniel,
> 
> here are the tests:
> 
> TEST-11
> ========
> Only HDMI connected.
> TV set on HDMI input.
> Reboot.
> The login screen uses the wrong resolution and
> it's in the wrong position as usual.
> I connected over VNC to login.
> Strangely now there is no split screen anymore
> (I checked and I'm using 3.2.0-drm-intel-fixes+)
> the screen is black and the resolution is 1024x768
> (I can see from VNC)
> xrandr --output HDMI2 --mode 1024x768 --rate 60.0
> (as expected no change since it's the actual res)
> xrandr --output HDMI2 --mode 1280x720 --rate 60.0
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 1280x720 --rate 50.0
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 800x600 --rate 60.3
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 800x600 --rate 60.3
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 720x480 --rate 59.9
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 640x480 --rate 59.9
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> xrandr --output HDMI2 --mode 640x480 --rate 60.0
> (the TV does something, but then goes back to black
> resolution is correct from VNC)
> I didn't save any dump cause you requested one where HDMI was working
> and it never did.
> Any idea?
> My question is: why I don't even see the split screen anymore
> and just the black screen?
> So, just to test, I run with 3.0.0-15-generic-pae and indeed
> I can see the split screen again. Also, the login screen
> is 1024x768 (split) rather than 1280x720 (when I run 3.2.0-drm-intel-fixes+)
> In 3.0.0-15-generic-pae, I can see the split screen but xrandr -q
> reports way less combinations (1024x768 at 60.0, 800x600 at 60.3, 640x480 at 60).
> I tried all three and they all "work" in split screen w/o flickering.
> The TV goes never "black".
> 
> > It just needs to be a HDMI-only configuration that works.
> 
> So if I understand your request correctly, I don't have such situation
> with only HDMI.

Have you booted with nomodeset and are using the vesa X driver? Iirc
you've said that the bios can setup up things correctly, the idea is to
grab a register dump to learn how the bios sets things up.

> AGAIN, as soon as I connect the VGA cable the TV is not in split
> screen anymore and I can see just fine.
> But you already have this test from the previous time so I won't take any log.
> 
> >
> > Test with the i915 driver (i.e. no nomodeset on the kernel cmdline),
> > if you want you can try both VGA cable only and VGA/HDMI but it
> > shouldn't matter. xrandr -q output shows only 55.4 and 60.0 for this
> > resolution, so I think it doesn't make sense to test anything else.
> 
> TEST-12
> ========
> VGA and HDMI connected.
> TV set on VGA input.
> Reboot.
> The login screen is black.
> I connected over VNC to login (login screen is 1024x768)
> 
> xrandr --output VGA1 --mode 1024x768 --rate 54.4
> (nothing changes, as expected)
> xrandr --output VGA1 --mode 1024x768 --rate 60.0
> bingo. I can see the screen with quite a bit of overscan top and bottom
> (exactly as I usually saw it over VGA from XP)
> 
> I also tried the same test with only VGA cable connected and it works
> the same way.
> 
> xrandr --output VGA1 --mode 800x600 --rate 60.3
> also works like in windows, with overscan.
> 
> I attached logs from 1024x768.
> 
> So, to conclude, I think we achieved feature parity over VGA. It's
> just a matter
> of choosing the right refresh rate...

Yeah, I kinda suspected that XP just picks the highest refresh rate. And
likely no one ever tested your TV with anything else than XP, so that
could explain why the lower refresh rate is b0rked :(

> Do you have any idea about the next step for HDMI?

Sorry, I couldn't yet look into the details. Will do it this week. It also
looks like someone else descovered the missing ingredient for interlaced
support on newer chipset, so it looks like we're on track to enable 1080i
on your TV (well, hopefully).
-Daniel
-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48