Set DuoView flag depending on active outputs

The DuoView flag only needs to be set if TV and another output
is active.

Signed-off-by: Hans-Juergen Mauser <hjmauser@gmx.net>
[Tormod: patch split out from a big diff]
Signed-off-by: Tormod Volden <debian.tormod@gmail.com>

3 files changed, 57 insertions, 0 deletions

diff --git a/src/savage_driver.h b/src/savage_driver.h
index 9849fdf..355a0f0 100644
--- a/src/savage_driver.h
+++ b/src/savage_driver.h
@@ -620,6 +620,7 @@ void SavageSetVESAMode( SavagePtr psav, int n, int Refresh );
 void SavageSetPanelEnabled( SavagePtr psav, Bool active );
 void SavageFreeBIOSModeTable( SavagePtr psav, SavageModeTablePtr* ppTable );
 int SavageGetTV( SavagePtr psav );
+int SavageCorrectDuoViewFlag(int iDevInfo, Bool bEnableActivate, Bool bEnableDeactivate);
 SavageModeTablePtr SavageGetBIOSModeTable( SavagePtr psav, int iDepth );
 ModeStatus SavageMatchBiosMode(ScrnInfoPtr pScrn,int width,int height,int refresh,
                               unsigned int *vesaMode,unsigned int *newRefresh);
diff --git a/src/savage_regs.h b/src/savage_regs.h
index 66cb215..0175fc1 100644
--- a/src/savage_regs.h
+++ b/src/savage_regs.h
@@ -200,6 +200,8 @@ do {                                    \
 #define CRT_ATTACHED	0x10
 #define LCD_ATTACHED	0x20
 #define TV_ATTACHED	0x40
+/* flag for DuoView, use identical naming to s3switch */
+#define DUO_ON	0x80
 /* flag to mask away anything but the active devices (x_ACTIVE) */
 #define ACTIVE_DEVICES	0x07
 
diff --git a/src/savage_vbe.c b/src/savage_vbe.c
index 31da072..c2e6000 100644
--- a/src/savage_vbe.c
+++ b/src/savage_vbe.c
@@ -179,6 +179,9 @@ SavageSetVESAMode( SavagePtr psav, int n, int Refresh )
 	psav->CrtOnly = (((psav->iDevInfo & ACTIVE_DEVICES) & ((unsigned char) ~CRT_ACTIVE)) == 0);
     }
 
+    /* fully adjust the DuoView flag */
+    psav->iDevInfo = SavageCorrectDuoViewFlag(psav->iDevInfo, TRUE, TRUE);
+
     /* Establish the refresh rate for this mode. */
 
     SavageClearVM86Regs( psav->pVbe->pInt10 );
@@ -304,6 +307,57 @@ int SavageGetTV( SavagePtr psav )
     return ((psav->pVbe->pInt10->cx) & 0xc); /* TV mode bits are bits 2 and 3 */
 }
 
+/* Function to correct the DuoView flag in the case of a single display */
+
+int SavageCorrectDuoViewFlag(int iDevInfo, Bool bEnableActivate,
+			     Bool bEnableDeactivate)
+{
+    /* TODO: limit this function to be used only if no multi view mode is
+     * active ("real" DuoView) */
+
+    /*
+     * This function can be used to correctly set the DuoView flag in case of
+     * a single X display. It operates directly on an "iDevInfo" bit field, so
+     * the caller has the choice which one should be checked.
+     *
+     * The DuoView flag is only necessary as soon as the TV output is involved.
+     * Logic derived from the behaviour of the hardware features of HP XE3:
+     * - if LCD or CRT or both are active and TV is NOT active, DuoView NEVER
+     *   needs to be set
+     * - if TV is the only active output, DuoView also does NOT need to be set
+     * - if TV is active together with LCD or CRT or both, DuoView MUST be set
+     *   to allow all outputs to work
+     *
+     * The two Bool flags allow the caller to set which operations should be
+     * done on the bit field.
+     * To use the full logic mentioned above, set both flags to TRUE.
+     */
+
+    Bool bDoEnable = FALSE;
+    int iNewDevInfo = iDevInfo;
+
+    /* decision logic */
+    /* only use iDevInfo here to avoid side effects on the return value */
+    if ((iDevInfo & TV_ACTIVE) != 0) { /* TV enabled, check if either CRT or LCD is also on */
+	if (((iDevInfo & CRT_ACTIVE) != 0)
+	    || ((iDevInfo & LCD_ACTIVE) != 0)) {
+		bDoEnable = TRUE;
+	}
+    }
+
+    /* action logic */
+    if (bDoEnable == TRUE) {
+	if (bEnableActivate == TRUE) {
+	    iNewDevInfo |= DUO_ON;
+	}
+    } else { /* bDoEnable == FALSE */
+	if (bEnableDeactivate == TRUE) {
+	    iNewDevInfo &= ~DUO_ON;
+	}
+    }
+
+    return iNewDevInfo;
+}
 
 void
 SavageFreeBIOSModeTable( SavagePtr psav, SavageModeTablePtr* ppTable )