Re: [Linuxwacom-discuss] xsetwacom MapToOutput with Nvidia drivers?

[James P. <ja...@mo...>]

Jason Gerecke wrote:
> 
> Thanks for checking up on this -- I don't think anyone has
> re-evaluated the state of nVidia xrandr support since that code was
> written way back in 2011.
> 
> The "we depend on RandR 1.3" comment definitely appears to be inaccurate.
> 
> As for the version check, I believe the problem is that
> XRRQueryVersion returns the version supported by the server, but
> there's no way to know if the driver actually supports it or not (see
> https://bugzilla.freedesktop.org/show_bug.cgi?id=16741). An old driver
> on a new server wouldn't work as expected. Do you know if the oldest
> still-supported version of the binary nVidia drivers can use the RandR
> codepath successfully? If so, then we can probably just get rid of the
> check entirely. Otherwise, we'd probably have to find a way to get the
> nVidia driver version to see if the RandR codepath can be used or not.

I have no idea what version of the Nvidia driver first supported what 
xsetwacom needs ... not my area of knowledge :-)

I guess it would be easier to remove the "NV-CONTROL" check - but still 
allow the use of the 'HEAD-X' syntax by swapping the 
set_output_xinerama()/set_output_xrandr() order in set_output()

i.e. if the real 'monitor name' is given and the Nvidia driver version 
doesn't support its use, then the code will still fail - but just in a 
different place. But if the Nvidia driver version does support it, then 
all is OK ...

I think the following patch may work

Thanks

James Pearson

--- ./tools/xsetwacom.c.dist    2016-08-08 01:06:24.000000000 +0100
+++ ./tools/xsetwacom.c 2018-04-04 11:05:25.289785549 +0100
@@ -2171,11 +2171,9 @@ static Bool need_xinerama(Display *dpy)
         int maj, min;

         if (!XQueryExtension(dpy, "RANDR", &opcode, &event, &error) ||
-           !XRRQueryVersion(dpy, &maj, &min) || (maj * 1000 + min) < 
1002 ||
-           XQueryExtension(dpy, "NV-CONTROL", &opcode, &event, &error))
+           !XRRQueryVersion(dpy, &maj, &min) || (maj * 1000 + min) < 1002)
         {
-               TRACE("RandR extension not found, too old, or NV-CONTROL "
-                       "extension is also present.\n");
+               TRACE("RandR extension not found or too old.\n");
                 return True;
         }

@@ -2555,10 +2553,10 @@ static void set_output(Display *dpy, XDe
                 set_output_next(dpy, dev);
         else if (strcasecmp(argv[0], "desktop") == 0)
                 set_output_desktop(dpy, dev);
-       else if (!need_xinerama(dpy))
-               set_output_xrandr(dpy, dev, argv[0]);
         else if  (convert_value_from_user(param, argv[0], &head_no))
                 set_output_xinerama(dpy, dev, head_no);
+       else if (!need_xinerama(dpy))
+               set_output_xrandr(dpy, dev, argv[0]);
         else
                 fprintf(stderr, "Unable to find an output '%s'.\n", 
argv[0]);
  }