Nouveau - Jan 2017 - [PATCH 5/6] drm: Delete "mandatory" stereographic modes

On Wed, Jan 18, 2017 at 11:57 AM, Ilia Mirkin <imirkin at alum.mit.edu>
wrote:
> On Wed, Jan 18, 2017 at 11:41 AM, Damien Lespiau
> <damien.lespiau at intel.com> wrote:
>> On Wed, Jan 18, 2017 at 04:33:43PM +0000, Damien Lespiau wrote:
>>> On Wed, Jan 18, 2017 at 11:27:16AM -0500, Ilia Mirkin wrote:
>>> > Damien - did you ever test these mandatory modes on an actual
>>> > commercial 3D TV or similar device?
>>>
>>> My main testing device was a Samsung TV with this 3D_present bit
set and
>>> all the advertised modes were working. Can't quite remember if
that
>>> included the interleaved mode.
>>
>> I even pushed the EDID of that TV to edid-decode [1] if someone needs
to
>> check that the EDID parsing is correct. It'd be interesting to see
what
>> the tool has to say about the edid of the sink causing problems, in
>> particular compare the mandatory modes to the other modes advertised by
>> that TV. Maybe we could see some kind of pattern emerge, like the 3D
>> modes supported being the ones with the timings in table 8-15.
>
> This is Alastair's display (one of them):
http://paste.lisp.org/display/335893
>
> I believe this is the interesting part:
>
>   Video data block
>     VIC  16 1920x1080 at 60Hz
>     VIC  31 1920x1080 at 50Hz
>     VIC   5 1920x1080i at 60Hz
>     VIC  20 1920x1080i at 50Hz
>     VIC   4 1280x720 at 60Hz
>     VIC  19 1280x720 at 50Hz
>     VIC   3 720x480 at 60Hz
>     VIC   2 720x480 at 60Hz
>     VIC  18 720x576 at 50Hz
>     VIC  17 720x576 at 50Hz
>     VIC   7 1440x480i at 60Hz
>     VIC   6 1440x480i at 60Hz
>     VIC  22 1440x576i at 50Hz
>     VIC  21 1440x576i at 50Hz
>     VIC  32 1920x1080 at 24Hz
>     VIC   1 640x480 at 60Hz
> ...
>     Extended HDMI video details:
>       3D present
>       Base EDID image size is in units of 1cm
>       VIC index 2 supports side-by-side (half, horizontal)
>       VIC index 3 supports side-by-side (half, horizontal)
>       VIC index 4 supports side-by-side (half, horizontal)
>       VIC index 5 supports side-by-side (half, horizontal)
>       VIC index 14 supports side-by-side (half, horizontal)
>       VIC index 0 supports top-and-bottom
>       VIC index 1 supports top-and-bottom
And for the record, this is his other TV (available at the same paste
url as above):

  Video data block
    VIC  16 1920x1080 at 60Hz (native)
    VIC  34 1920x1080 at 30Hz
    VIC  32 1920x1080 at 24Hz
    VIC   5 1920x1080i at 60Hz
    VIC   4 1280x720 at 60Hz
    VIC   3 720x480 at 60Hz
    VIC   2 720x480 at 60Hz
    VIC   1 640x480 at 60Hz
    Extended HDMI video details:
      3D present
      3D-capable-VIC mask present
      3D: Side-by-side (half, horizontal)
      3D: Top-and-bottom
      3D VIC indices: 2 4
      VIC index 0 supports side-by-side (half, horizontal)
      VIC index 1 supports side-by-side (half, horizontal)
      VIC index 2 supports side-by-side (half, horizontal)
      VIC index 3 supports side-by-side (half, horizontal)
      VIC index 4 supports side-by-side (half, horizontal)

After some more conversations with Alastair, it sounds like what's
actually going on is that it's just the frame-packing modes that
aren't working, but all the side-by-side and top-and-bottom modes from
the "mandatory" list work. At this point, I'm more inclined to
believe
that there's an issue in the nouveau implementation for frame-packed
modes. But it could still be the TVs themselves that don't support
that at all.

Cheers,

  -ilia

On Wed, Jan 18, 2017 at 01:48:04PM -0500, Ilia Mirkin
wrote:
> After some more conversations with Alastair, it sounds like what's
> actually going on is that it's just the frame-packing modes that
> aren't working, but all the side-by-side and top-and-bottom modes from
> the "mandatory" list work. At this point, I'm more inclined
to believe
> that there's an issue in the nouveau implementation for frame-packed
> modes. But it could still be the TVs themselves that don't support
> that at all.
If Alastair has an intel GPU as well, an "easy" way to check if the
frame packing modes of those TVs work would be to use the testdisplay[1]
tool of intel-gpu-tools.

Shameless plug: http://damien.lespiau.name/2013/10/hdmi-stereo-3d-kms.html

Towards the end of the post, there are test display usage examples to go
and test FP modes. Mind you, people have been trying to make
intel-gpu-tools run on any DRM driver when possible, not sure how far we
are with that though.

-- 
Damien

[1]
http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/tree/tests/testdisplay.c

On Wed, Jan 18, 2017 at 2:01 PM, Damien Lespiau <damien.lespiau at
intel.com>
wrote:
>
> On Wed, Jan 18, 2017 at 01:48:04PM -0500, Ilia Mirkin wrote:
> > After some more conversations with Alastair, it sounds like what's
> > actually going on is that it's just the frame-packing modes that
> > aren't working, but all the side-by-side and top-and-bottom modes
from
> > the "mandatory" list work. At this point, I'm more
inclined to believe
> > that there's an issue in the nouveau implementation for
frame-packed
> > modes. But it could still be the TVs themselves that don't support
> > that at all.
By now, and having re-read the relevant spec extract a couple of times,
I'm convinced that the "mandatory" stereographic modes are just
that, but
also that the current implementation is incorrect (if anything, too
conservative about adding modes).  In the unlikely event that a display
advertises only a 512x384x1bpp at 60Hz mode (I don't even know if that's
possible in terms of an EDID, but let's take it as an example), but also
sets the 3D flag, it must support five specific 3D modes, but the current
implementation would match none.

I'm definitely willing to table changing the mandatory mode logic for the
time being, at least until the question of frame packing on my hardware
is sorted out.
> If Alastair has an intel GPU as well, an "easy" way to check if
the
> frame packing modes of those TVs work would be to use the testdisplay[1]
> tool of intel-gpu-tools.
If I have an intel GPU handy, I think that it's getting disabled by the
system BIOS or something due to hardware configuration.  I have a couple
of things to try, and there might be a machine with an intel GPU that I
can borrow next week, though.

Should any intel GPU with an HDMI output work, or do I need to look for
something more specific?

I should also have access to the restore disks that came with some of my
hardware as of this weekend, so I can see what the, ah, *other* operating
system has to say about things.
> Shameless plug: http://damien.lespiau.name/2013/10/hdmi-stereo-3d-kms.html
I had found this, which led me to intel-gpu-tools, and thus testdisplay,
which is what I've been using.  It's a very nice explanation of how
things
should work overall...  But it calls one question to mind: Is there userland
software other than testdisplay that does anything with stereo 3D support?
> Towards the end of the post, there are test display usage examples to go
> and test FP modes. Mind you, people have been trying to make
> intel-gpu-tools run on any DRM driver when possible, not sure how far we
> are with that though.
... Which raises the number of possibilities that we're dealing with to
three:

 1. The displays really don't support frame packing.

 2. There's something not yet right with nouveau that breaks frame packing.

 3. There's something not yet right with testdisplay that breaks frame
packing
    on nouveau (I had previously presumed that testdisplay wasn't going to
be
    a problem, but it sounds like it might be worth me digging into).
> --
> Damien
>
> [1]
http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/tree/tests/testdisplay.c

-- Alastair
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