Attachment 313848 Details for Bug 457685 – xscreensaver nvidia bug workaround

[patch] xscreensaver nvidia bug workaround

nvidia-patch.txt (text/plain), 8.32 KB, created by Jamie Zawinski on 2008-08-08 21:10:37 UTC

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Creator: Jamie Zawinski

Created: 2008-08-08 21:10:37 UTC

Size: 8.32 KB

patch

obsolete

>Index: screens.c
>===================================================================
>RCS file: /cvsroot/xscreensaver/driver/screens.c,v
>retrieving revision 1.7
>retrieving revision 1.12
>diff -u -r1.7 -r1.12
>--- screens.c	8 Jul 2008 05:22:46 -0000	1.7
>+++ screens.c	8 Aug 2008 21:06:07 -0000	1.12
>@@ -98,6 +98,16 @@
>  *      to put seperate savers on those duplicated-or-overlapping
>  *      monitors, xscreensaver just ignores them (which allows them to
>  *      display duplicates or overlaps).
>+ *
>+ *   5a) Nvidia fucks it up:
>+ *
>+ *      Nvidia drivers as of Aug 2008 running in "TwinView" mode
>+ *      apparently report correct screen geometry via Xinerama, but
>+ *      report one giant screen via RANDR.  The response from the
>+ *      nvidia developers is, "we don't support RANDR, use Xinerama
>+ *      instead."  Which is a seriously lame answer.  So, xscreensaver
>+ *      has to query *both* extensions, and make a guess as to which
>+ *      is to be believed.
>  */
> 
> #ifdef HAVE_CONFIG_H
>@@ -143,6 +153,9 @@
>   int enemy;			/* which monitor it overlaps or duplicates */
> };
> 
>+static Bool layouts_differ_p (monitor **a, monitor **b);
>+
>+
> static void
> free_monitors (monitor **monitors)
> {
>@@ -342,7 +355,7 @@
> 
>   for (i = 0, j = 0; i < ScreenCount (dpy); i++)
>     {
>-      Screen *screen = ScreenOfDisplay (dpy, j);
>+      Screen *screen = ScreenOfDisplay (dpy, i);
> 
>       if (! new_randr_p)  /* RANDR 1.0 */
>         {
>@@ -358,12 +371,17 @@
>               SizeID size = -1;
>               Rotation rot = ~0;
>               XRRScreenSize *rrsizes;
>-              int nsizes;
>+              int nsizes = 0;
> 
>               size = XRRConfigCurrentConfiguration (rrc, &rot);
>               rrsizes = XRRConfigSizes (rrc, &nsizes);
> 
>-              if (rot & (RR_Rotate_90|RR_Rotate_270))
>+              if (nsizes <= 0)  /* WTF?  Shouldn't happen but does. */
>+                {
>+                  m->width  = DisplayWidth (dpy, i);
>+                  m->height = DisplayHeight (dpy, i);
>+                }
>+              else if (rot & (RR_Rotate_90|RR_Rotate_270))
>                 {
>                   m->width  = rrsizes[size].height;
>                   m->height = rrsizes[size].width;
>@@ -454,6 +472,66 @@
> }
> 
> 
>+#if defined(HAVE_RANDR) && defined(HAVE_XINERAMA)
>+
>+/*   From: Aaron Plattner <aplattner@nvidia.com>
>+     Date: August 7, 2008 10:21:25 AM PDT
>+     To: linux-bugs@nvidia.com
>+
>+     The NVIDIA X driver does not yet support RandR 1.2.  The X server has
>+     a compatibility layer in it that allows RandR 1.2 clients to talk to
>+     RandR 1.1 drivers through an RandR 1.2 pseudo-output called "default".
>+     This reports the total combined resolution of the TwinView display,
>+     since it doesn't have any visibility into TwinView metamodes.  There
>+     is no way for the driver to prevent the server from turning on this
>+     compatibility layer.
>+
>+     The intention is for X client applications to continue to use the
>+     Xinerama extension to query the screen geometry.  RandR 1.2 reports
>+     its own Xinerama info for this purpose.  I would recommend against
>+     modifying xscreensaver to try to get this information from RandR.
>+ */
>+static monitor **
>+randr_versus_xinerama_fight (Display *dpy, monitor **randr_monitors)
>+{
>+  monitor **xinerama_monitors;
>+
>+  if (!randr_monitors) 
>+    return 0;
>+
>+  xinerama_monitors = xinerama_scan_monitors (dpy);
>+  if (!xinerama_monitors)
>+    return randr_monitors;
>+
>+  if (! layouts_differ_p (randr_monitors, xinerama_monitors))
>+    {
>+      free_monitors (xinerama_monitors);
>+      return randr_monitors;
>+    }
>+  else if (   randr_monitors[0] &&   !randr_monitors[1] &&  /* 1 monitor */
>+           xinerama_monitors[0] && xinerama_monitors[1])    /* >1 monitor */
>+    {
>+      fprintf (stderr,
>+               "%s: WARNING: RANDR reports 1 screen but Xinerama\n"
>+               "%s:          reports multiple.  Believing Xinerama.\n",
>+               blurb(), blurb());
>+      free_monitors (randr_monitors);
>+      return xinerama_monitors;
>+    }
>+  else
>+    {
>+      fprintf (stderr,
>+               "%s: WARNING: RANDR and Xinerama report different\n"
>+               "%s:          screen layouts!  Believing RANDR.\n",
>+               blurb(), blurb());
>+      free_monitors (xinerama_monitors);
>+      return randr_monitors;
>+    }
>+}
>+
>+#endif /* HAVE_RANDR && HAVE_XINERAMA */
>+
>+
> #ifdef DEBUG_MULTISCREEN
> 
> /* If DEBUG_MULTISCREEN is defined, then in "-debug" mode, xscreensaver
>@@ -557,13 +635,17 @@
> # ifdef HAVE_RANDR
>   if (! p->getviewport_full_of_lies_p)
>     if (! monitors) monitors = randr_scan_monitors (si->dpy);
>-# endif
>+
>+#  ifdef HAVE_XINERAMA
>+   monitors = randr_versus_xinerama_fight (si->dpy, monitors);
>+#  endif
>+# endif /* HAVE_RANDR */
> 
> # ifdef HAVE_XF86VMODE
>   if (! monitors) monitors = vidmode_scan_monitors (si->dpy);
> # endif
> 
>-# ifdef HAVE_XF86VMODE
>+# ifdef HAVE_XINERAMA
>   if (! monitors) monitors = xinerama_scan_monitors (si->dpy);
> # endif
> 
>@@ -598,6 +680,38 @@
> }
> 
> 
>+static Bool
>+plausible_aspect_ratio_p (monitor **monitors)
>+{
>+  /* Modern wide-screen monitors come in the following aspect ratios:
>+
>+            One monitor:        If you tack a 640x480 monitor
>+                                onto the right, the ratio is:
>+         16 x 9    --> 1.78
>+        852 x 480  --> 1.77        852+640 x 480  --> 3.11      "SD 480p"
>+       1280 x 720  --> 1.78       1280+640 x 720  --> 2.67      "HD 720p"
>+       1280 x 920  --> 1.39       1280+640 x 920  --> 2.09
>+       1366 x 768  --> 1.78       1366+640 x 768  --> 2.61      "HD 768p"
>+       1440 x 900  --> 1.60       1440+640 x 900  --> 2.31
>+       1680 x 1050 --> 1.60       1680+640 x 1050 --> 2.21
>+       1690 x 1050 --> 1.61       1690+640 x 1050 --> 2.22
>+       1920 x 1080 --> 1.78       1920+640 x 1080 --> 2.37      "HD 1080p"
>+       1920 x 1200 --> 1.60       1920+640 x 1200 --> 2.13
>+       2560 x 1600 --> 1.60       2560+640 x 1600 --> 2.00
>+
>+     So that implies that if we ever see an aspect ratio >= 2.0,
>+     we can be pretty sure that the X server is lying to us, and
>+     that's actually two monitors, not one.
>+   */
>+  if (monitors[0] && !monitors[1] &&    /* exactly 1 monitor */
>+      monitors[0]->height &&
>+      monitors[0]->width / (double) monitors[0]->height >= 1.9)
>+    return False;
>+  else
>+    return True;
>+}
>+
>+
> /* Mark the ones that overlap, etc.
>  */
> static void
>@@ -624,6 +738,7 @@
>       if (i != j &&
>           monitors[i]->sanity == S_SANE &&
>           monitors[j]->sanity == S_SANE &&
>+          monitors[i]->screen == monitors[j]->screen &&
>           X2 >= X1 &&
>           Y2 >= Y1 &&
>           (X2+W2) <= (X1+W1) &&
>@@ -648,6 +763,7 @@
>       {
>         if (monitors[i]->sanity != S_SANE) continue; /* already marked */
>         if (monitors[j]->sanity != S_SANE) continue;
>+        if (monitors[i]->screen != monitors[j]->screen) continue;
> 
>         if (monitors_overlap_p (monitors[i], monitors[j]))
>           {
>@@ -656,17 +772,15 @@
>           }
>       }
> 
>-  /* Finally, make sure all monitors are enclosed by their X screen.
>+  /* Finally, make sure all monitors have sane positions and sizes.
>      Xinerama sometimes reports 1024x768 VPs at -1936862040, -1953705044.
>    */
>   for (i = 0; i < count; i++)
>     {
>-      int sw = WidthOfScreen (monitors[i]->screen)  * 2;
>-      int sh = HeightOfScreen (monitors[i]->screen) * 2;
>       if (monitors[i]->sanity != S_SANE) continue; /* already marked */
>-      if (X1    <  0 || Y1    <  0 || 
>-          W1    <= 0 || H1    <= 0 || 
>-          X1+W1 > sw || Y1+H1 > sh)
>+      if (X1    <  0      || Y1    <  0 || 
>+          W1    <= 0      || H1    <= 0 || 
>+          X1+W1 >= 0x7FFF || Y1+H1 >= 0x7FFF)
>         {
>           monitors[i]->sanity = S_OFFSCREEN;
>           monitors[i]->enemy = 0;
>@@ -715,6 +829,8 @@
>   int count = 0;
>   int good_count = 0;
>   int bad_count = 0;
>+  int implausible_p = !plausible_aspect_ratio_p (monitors);
>+
>   while (monitors[count])
>     {
>       if (monitors[count]->sanity == S_SANE)
>@@ -778,6 +894,14 @@
>                 }
>             }
>         }
>+
>+      if (implausible_p)
>+        fprintf (stderr,
>+                 "%s: WARNING: single screen aspect ratio is %dx%d = %.2f\n"
>+                 "%s:          probable X server bug in Xinerama/RANDR!\n",
>+                 blurb(), monitors[0]->width, monitors[0]->height,
>+                 monitors[0]->width / (double) monitors[0]->height,
>+                 blurb());
>     }
> }
>

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Attachments on bug 457685: 313848