When switching from nv to nvidia driver lose screen resolution; nvidia doesn't use EDID freq. data even though that data is correct

nvidia driver, unlike nv driver, doesn't try to use EDID data that is correct

This is related to problem 3731. Possibly a dup of 105967, related to nvidia-glx

Its particular circumstances:

1. Resolution is fine with nv driver, but after using the Restricted Drivers Manager to
go from the nv driver to the nvidia driver high resolutions are lost

2. The monitor returns correct EDID data, as demonstrated by "xresprobe nv" and
"xresprobe nvidia".

My card uses the nvidia-glx-legacy drivers. I was trying to use compiz, but this
problem seems to be driver related, not compiz related. Because of compiz many
people with EDID compliant monitors might try to use the restricted driver manager
with nvidia cards, so this issue might grow in importance with the release of Gutsy.

Detail:

Examining the xorg.conf files and Xorg.0.log files I saw that the nvidia driver constrained
the resolution by comparing the requirements against a different, conservative, set
of HorizSync and VertRefresh settings--apparently driver defaults. The nv driver had been
using the monitor-returned EDID frequency results and was therefore allowing higher
resolutions.

Further examination of more detailed xorg logs showed that the nvidia driver was
retrieving the EDID frequency data, but just not using it.

Using the strings command on the nvidia X driver I saw the driver had an option called
"UseEDIDFreqs" . I found that the nvidia-xconfig program from the package of the
same name has an option of --use-edid-freqs which inserts the UseEDIDFreqs option into
the xorg.conf file.

Note that this program's advanced help (nvidia-xconfig -A) explains the option and
says that this option will override the HorizSync and VertRefresh ranges given in
the xorg.conf monitors section with the equipment returned EDID data.
I confirmed this through testing.

A Suggested solution:

Have Restricted Drivers Manager add another Option line to the xorg.conf output
when it changes it to use the nvidia driver--

 Option "UseEDIDFreqs" "True"

Sample code change to Restricted Drivers Manager nvidia.py, a one
line change:

=======================================================
--- nvidia.py_orig 2007-10-08 22:32:08.000000000 -0400
+++ nvidia.py_new 2007-10-09 16:34:39.000000000 -0400
@@ -38,21 +38,22 @@
         # compiz does not work otherwise
         self.xorg_conf.getSections('Screen')[0].defaultdepth = 24

 class LegacyNvidiaDriver(NvidiaDriver):
     is_handler = True

     name = "nvidia_legacy"

     def __init__(self, module):
         NvidiaDriver.__init__(self, module, "nvidia-glx-legacy",
- {"AllowGLXWithComposite": "True", "NoLogo": "True"})
+ {"AllowGLXWithComposite": "True", "NoLogo": "True",
+ "UseEdidFreqs": "True"})

     def description(self):
         return _("NVIDIA accelerated graphics driver (legacy cards)")

 class NewNvidiaDriver(NvidiaDriver):
     is_handler = True

     name = "nvidia_new"

     def __init__(self, module):
=========================================================

I tested the option by editing xorg.conf by hand. It worked for me.

I then made the above change to the restricted driver manager and
it successfully allowed the plug and play function of xorg to
enable the proper higher resolutions and set the resolution to the
resolution nv used.

(After the modification was made I used the restricted driver manager
to disable the restricted driver, then used it again to enable the
driver, running the modified code. That's what worked)

Note 1:

While this would help plug and play work with properly working monitors and video
cards, people with equipment returning bad EDID data with the nvidia restricted
driver would still like to override the horizontal and vertical frequencies by
way of the file. I was able to confirm that the nvidia driver will choose the
EDID information over the HorizSync and VertRefresh options in the xorg.conf file.

While plug and play with standards compliant equipment should probably be a priority,
the need to continue to address the needs of those with malfunctioning equipment
should probably continue to be addressed.

Perhaps the new displayconfig-gtk should add the
IgnoreEDID option so the xorg.conf file it produces will override the EDID data.
I confirmed through testing that with the nvidia driver the IgnoreEDID data does
overrule the UseEDIDFreqs option if both are present in the file. Perhaps
the insertion of IgnoreEDID by displayconfig-gtk in the monitor section
would be a good precaution anyway in case there is bad EDID data of other
sorts which might otherwise overrule the contents of the config file.

Note 2:

I'm a newbie and this is my first bug report. Please forgive and correct me
if I've violated any protocol or done anything wrong.