[ltp] Getting nVidia to clone display on a projector

[Alex Deucher]

On Tue, Nov 23, 2010 at 12:50 PM, John Jason Jordan <johnxj@comcast.net> wr=
ote:
> On Tue, 23 Nov 2010 15:24:09 +0200
> Micha Feigin <michf@post.tau.ac.il> dijo:
>
>>On Mon, 22 Nov 2010 15:13:47 -0800
>>John Jason Jordan <johnxj@comcast.net> wrote:
>>
>>> On Mon, 22 Nov 2010 23:23:52 +0200
>>> Micha Feigin <michf@post.tau.ac.il> dijo:
>>>
>>> >> The problem that remains, however, is getting my laptop screen to
>>> >> display anything other than 1680x1050. I am currently using the
>>> >> latest nVidia driver with Fedora 13, x86_64, and it allows me to
>>> >> select:
>
>>> That is what the xorg.conf file created by the nVidia installer says
>>> on my computer too. So you're saying the reason I get the option of
>>> 1680x1050, and nothing lower until I go all the way down to 1280x1024
>>> is because the nVidia driver decided that the intervening resolutions
>>> wouldn't work at the above sync and refresh rates?
>
>>Like I said. I used to have that problem. I don't know if it was a
>>problem with the edid the screen sent or something with the xserver /
>>nvidia driver, etc.
>>
>>I used to need the linked approach to create a custom edid file.
>>Currently everything works fine on my laptop, so there was some
>>software bug along the way that nouveau doesn't suffer from and nvidia
>>does.
>
> I have since discovered a utility called monitor-edid. This tool polls
> the screen for its E-DID data and displays it on the command line. For
> my T61 it says:

Note that that utility probably uses vbe (vesa bios extensions) to
query the EDID and vbe is not multi-head aware.  The only way to query
the EDID info is to query the the info from the i2c bus on each
connector which is generally something the driver has to do.

Alex

>
> [root@Devil8 X11]# monitor-edid
> EISA ID: IBM2887
> EDID version: 1.3
> EDID extension blocks: 0
> Screen size: 33.1 cm x 20.7 cm (15.37 inches, aspect ratio 16/10 =3D 1.60=
)
> Gamma: 2.2
> Digital signal
> =A0 =A0 =A0 =A0# Monitor preferred modeline (60.0 Hz vsync, 63.9 kHz hsyn=
c,
> =A0 =A0 =A0 =A0ratio 16/10, 128 dpi) ModeLine "1680x1050" 120.6 1680 1712=
 1760
> =A0 =A0 =A0 =A01888 1050 1051 1054 1065 -hsync -vsync
> =A0 =A0 =A0 =A0# Monitor supported modeline (50.0 Hz vsync, 53.2 kHz hsyn=
c,
> =A0 =A0 =A0 =A0ratio 16/10, 128 dpi) ModeLine "1680x1050" 100.53 1680 171=
2
> =A0 =A0 =A0 =A01760 1888 1050 1051 1054 1065 -hsync -vsync
>
> It is interesting that the only resolution the E-DID data from the
> screen reports is 1680x1050. I also note from the Xorg.o.log file this
> part (edited for readability):
>
> [ =A0 532.284] (--) NVIDIA(0): Connected display device(s) on Quadro NVS
> =A0 =A0 =A0 =A0140M at PCI:1:0:0
> [ =A0 532.284] (--) NVIDIA(0): IBM (DFP-0)
> [ =A0 532.285] (--) NVIDIA(0): IBM (DFP-0): 330.0 MHz maximum pixel clock
> [ =A0 532.285] (--) NVIDIA(0): IBM (DFP-0): Internal Dual Link LVDS
> [ =A0 532.290] (WW) NVIDIA(0): The EDID for IBM (DFP-0) contradicts
> =A0 =A0 =A0 =A0itself: mode "1680x1050" is specified in the EDID; however=
, the
> =A0 =A0 =A0 =A0EDID's valid HorizSync range (53.246-63.877 kHz) would exc=
lude
> =A0 =A0 =A0 =A0this =A0mode's HorizSync (42.6 kHz); ignoring HorizSync ch=
eck for
> =A0 =A0 =A0 =A0mode "1680x1050".
> [ =A0 532.290] (WW) NVIDIA(0): The EDID for IBM (DFP-0) contradicts
> =A0 =A0 =A0 =A0itself: mode "1680x1050" is specified in the EDID; however=
, the
> =A0 =A0 =A0 =A0EDID's valid HorizSync range (53.246-63.877 kHz) would exc=
lude
> =A0 =A0 =A0 =A0this mode's HorizSync (42.6 kHz); ignoring HorizSync check=
 for
> =A0 =A0 =A0 =A0mode "1680x1050".
> [ =A0 532.341] (II) NVIDIA(0): Assigned Display Device: DFP-0
> [ =A0 532.341] (II) NVIDIA(0): Validated modes:
> =A0 =A0 =A0 =A0"nvidia-auto-select"
> [ =A0 532.341] (II) NVIDIA(0):
> =A0 =A0 =A0 =A0Virtual screen size determined to be 1680 x 1050
>
> It looks to me like the E-DID data in the screen is messed up.
> Furthermore, it looks like the E-DID data reports only one possible
> resolution. That leads me to wonder where the nVidia driver came up
> with the other resolutions that it presents to me: 1280x1024, etc. They
> do work, but apparently the driver made them up. When I booted to Lucid
> live CD with the nouveau driver it probably did the same thing, except
> that intelligently offered me 1400x1050 as the next resolution after
> 1680x1050.
>
> I also discovered a shareware utility called Powerstrip that apparently
> can modify the E-DID data in a monitor. Unfortunately it runs only on
> Windows, and the only Windows I have on this computer is running in
> Virtualbox. Powerstrip is also scary. It's working OK at 1680x1050;
> what if I mess it up and it won't work at all?
>
> It would be interesting if there are any other people here who have a
> 15.4" T61 with the nVidia Quadro NVS 140M. Comparing notes might be
> useful.
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