ports/155011: nvidia-settings versions 195 and above fail to allow display configuration with legacy nvidia-driver versions

[Tom Russo]

>Number:         155011
>Category:       ports
>Synopsis:       nvidia-settings versions 195 and above fail to allow display configuration with legacy nvidia-driver versions
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Feb 24 21:20:08 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Tom Russo
>Release:        7.4-PRERELEASE
>Organization:
>Environment:
FreeBSD bogodyn.org 7.4-PRERELEASE FreeBSD 7.4-PRERELEASE #0: Sat Jan  1 21:48:22 MST 2011     russo at bogodyn.org:/users2/obj/usr/src/sys/BOGODYN  i386

>Description:
Beginning with nvidia-settings 195 and ever since, the "X Server Display Configuration" panel has produced an error "Failed to query NoScanout for screen 0" and refused to allow display configuration if a "legacy" version of the driver is installed (e.g. nvidia-driver-71, nvidia-driver-95 or nvidia-driver-173).  That is because the "NoScanout" property was added in nvidia-driver 195, and the settings program treats not finding it as an error, guaranteeing that the latest nvidia-settings will be broken when used on a machine with legacy drivers.

Unless the nvidia-settings port is tweaked to install versions of nvidia-settings matching the installed driver, nvidia-settings needs to be patched in order to prevent this breakage.

>How-To-Repeat:
Install an older NVIDIA video card requiring a legacy NVIDIA driver and install the appropriate legacy driver.  Install the latest nvidia-settings port (which at this time is version 270.18).  Run nvidia-settings and click "X Server Display Configuration."  You will get a screen that shows "Unable to load X Server Display Configuration Page:  Failed to query NoScanout for screen 0."  There is at that point no way to manipulate display configuration through the GUI.
>Fix:
The attached patch comments out the code that treats a missing NoScanout property as an error, and returns instead a response to indicate NoScanout is disabled.

This patch is copied from Ubuntu's bug tracker, where it is part of the nvidia-settings package build process.

http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/lucid/nvidia-settings/lucid/revision/27

This patch allows nvidia-settings' X Server Display Configuration panel to work properly with legacy nvidia-driver ports.

The only difference between the attached patch and Ubuntu's is that I have used  "#if 0/#endif" preprocessor directives to disable the code rather than C comments.

Patch attached with submission follows:

--- src/gtk+-2.x/ctkdisplayconfig-utils.c.orig	2011-02-24 13:55:03.000000000 -0700
+++ src/gtk+-2.x/ctkdisplayconfig-utils.c	2011-02-24 13:56:05.000000000 -0700
@@ -2103,11 +2103,14 @@
     /* See if the screen is set to not scanout */
     ret = NvCtrlGetAttribute(screen->handle, NV_CTRL_NO_SCANOUT, &val);
     if (ret != NvCtrlSuccess) {
+#if 0
         *err_str = g_strdup_printf("Failed to query NoScanout for "
                                    "screen %d.",
                                    screen_id);
         nv_warning_msg(*err_str);
         goto fail;
+#endif
+        val = NV_CTRL_NO_SCANOUT_DISABLED;
     }
     screen->no_scanout = (val == NV_CTRL_NO_SCANOUT_ENABLED);
 


>Release-Note:
>Audit-Trail:
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