Fix black screen after resume from hibernate.

The root cause for the black screen and system lock up is
caused by not recovering the SVGA ID register after hibernation.
Incorrect ID register value will invalidate the FIFO memory start
register, and driver will not retrieve correct FIFO memory start
address and the busy read of svga FIFO sync register will lock up
the whole system.

Currently SVGA Xorg driver does not have a kernel module to handle
the power management event, but Xorg will call driver provided
LeaveVT before shutting down system and call EnterVT after resuming
system from hibernation, so these two callback functions are good
entry points to save and restore the ID register value. This patch
saves the ID register value in LeaveVT and restores the value to
SVGA ID register in EnterVT.

2 files changed, 17 insertions, 1 deletions

diff --git a/src/vmware.c b/src/vmware.c
index ef2dedb..069cf2c 100644
--- a/src/vmware.c
+++ b/src/vmware.c
@@ -652,6 +652,7 @@ VMWAREPreInit(ScrnInfoPtr pScrn, int flags)
                    "No supported VMware SVGA found (read ID 0x%08x).\n", id);
         return FALSE;
     }
+    pVMWARE->suspensionSavedRegId = id;
 
 #if !XSERVER_LIBPCIACCESS
     pVMWARE->PciTag = pciTag(pVMWARE->PciInfo->bus, pVMWARE->PciInfo->device,
@@ -1820,7 +1821,13 @@ VMWAREEnterVT(int scrnIndex, int flags)
     ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
     VMWAREPtr pVMWARE = VMWAREPTR(pScrn);
 
-    if (!pVMWARE->SavedReg.svga_fifo_enabled) {
+    /*
+     * After system resumes from hiberation, EnterVT will be called and this
+     * is a good place to restore the SVGA ID register.
+     */
+    vmwareWriteReg(pVMWARE, SVGA_REG_ID, pVMWARE->suspensionSavedRegId);
+
+    if (!pVMWARE->SavedReg.svga_fifo_enabled) {       
         VMWAREInitFIFO(pScrn);
     }
 
@@ -1831,6 +1838,14 @@ static void
 VMWARELeaveVT(int scrnIndex, int flags)
 {
     ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
+    VMWAREPtr pVMWARE = VMWAREPTR(pScrn);
+
+    /*
+     * Before shutting down system for hibneration, LeaveVT will be called,
+     * we save the ID register value here and later restore it in EnterVT.
+     */
+    pVMWARE->suspensionSavedRegId = vmwareReadReg(pVMWARE, SVGA_REG_ID);
+
     VMWARERestore(pScrn);
 }
 
diff --git a/src/vmware.h b/src/vmware.h
index 57872b2..b906ff2 100644
--- a/src/vmware.h
+++ b/src/vmware.h
@@ -102,6 +102,7 @@ typedef struct {
 
     VMWARERegRec SavedReg;
     VMWARERegRec ModeReg;
+    CARD32 suspensionSavedRegId;
 
     DisplayModePtr dynModes[NUM_DYN_MODES];