Changeset 75939 in vbox

Timestamp:

Dec 4, 2018 9:12:54 AM (6 years ago)

Author:

vboxsync

Message:

Graphics/VMSVGA: return 32, not 1 from SVGA_REG_NUM_DISPLAYS register.
bugref:9170: Implement support for multihead display configurations in VMSVGA device.
The current Linux driver treats the value returned from the
SVGA_REG_NUM_DISPLAYS register as a hard upper limit on the number of guest
displays, so increase it to 32. Now I can enable a second display in an
Ubuntu 18.04 guest.

File:

• trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp (modified) (1 diff)

trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp

@@ -1218 +1218 @@
     case SVGA_REG_NUM_DISPLAYS:        /* (Deprecated) */
         STAM_REL_COUNTER_INC(&pThis->svga.StatRegNumDisplaysRd);
-        /** @todo keep 1? */
-        *pu32 = 1;  /* Must return something sensible here otherwise the Linux driver will take a legacy code path without 3d support. */
+        /* We must return something sensible here otherwise the Linux driver
+         * will take a legacy code path without 3d support.  This number also
+         * limits how many screens Linux guests will allow. */
+        *pu32 = 32;
         break;