Use the CRT Monitor Detect MSOC register.

  Probably I misunderstood the usage of this register, as it will always
show the same value, regardless of having a crt connected to the "vga"
port or not. Only difference is that while the detect bit is set,
the crt will be blank. This patch should be more of a placeholder for
a possible correction, but it should not cause any side effects, unless
the data field can be zero on a valid situation.
  In my test computer, this field, in base 2 is always 1000000010000100,
what doesn't really look like data in rgb 8:8:8...

3 files changed, 51 insertions, 3 deletions

diff --git a/src/smi501_output.c b/src/smi501_output.c
index 7a22955..4652344 100644
--- a/src/smi501_output.c
+++ b/src/smi501_output.c
@@ -97,9 +97,33 @@ SMI501_OutputDPMS_crt(xf86OutputPtr output, int dpms)
 static xf86OutputStatus
 SMI501_OutputDetect_crt(xf86OutputPtr output)
 {
+    ScrnInfoPtr		pScrn = output->scrn;
+    SMIPtr		pSmi = SMIPTR(pScrn);
+    MSOCRegPtr		mode = pSmi->mode;
+    xf86OutputStatus	status;
+
     ENTER();
 
-    RETURN(XF86OutputStatusDisconnected);
+    mode->crt_detect.value = READ_SCR(pSmi, CRT_DETECT);
+    mode->crt_detect.f.enable = 1;
+    WRITE_SCR(pSmi, CRT_DETECT, mode->crt_detect.value);
+    SMI501_WaitVSync(pSmi, 1);
+
+    mode->crt_detect.value = READ_SCR(pSmi, CRT_DETECT);
+
+    /* FIXME This appears to have a fixed value, whatever I do, and
+     * the binary pattern is 1000000010000100
+     * regardless of crt being connected or not, so maybe this is
+     * just telling there is a VGA output?
+     */
+    status = mode->crt_detect.f.data ?
+	XF86OutputStatusConnected : XF86OutputStatusUnknown;
+
+    mode->crt_detect.f.enable = 0;
+    WRITE_SCR(pSmi, CRT_DETECT, mode->crt_detect.value);
+    SMI501_WaitVSync(pSmi, 1);
+
+    RETURN(status);
 }
 
 static xf86OutputFuncsRec SMI501_Output0Funcs;
@@ -133,6 +157,7 @@ SMI501_OutputPreInit(ScrnInfoPtr pScrn)
 	SMI_OutputFuncsInit_base(&SMI501_Output1Funcs);
 	SMI501_Output1Funcs.dpms	= SMI501_OutputDPMS_crt;
 	SMI501_Output1Funcs.get_modes	= SMI_OutputGetModes_native;
+	SMI501_Output1Funcs.detect	= SMI501_OutputDetect_crt;
 
 	output1 = xf86OutputCreate(pScrn, &SMI501_Output1Funcs, "VGA");
 	if (!output1)
diff --git a/src/smi_501.c b/src/smi_501.c
index 555dfd8..2f993ca 100644
--- a/src/smi_501.c
+++ b/src/smi_501.c
@@ -50,7 +50,6 @@ authorization from The XFree86 Project or Silicon Motion.
 static char *format_integer_base2(int32_t word);
 static void SMI501_SetClock(SMIPtr pSmi, int32_t port,
 			    int32_t pll, int32_t value);
-static void SMI501_WaitVSync(SMIPtr pSmi, int vsync_count);
 
 
 /*
@@ -517,7 +516,7 @@ SMI501_PrintRegs(ScrnInfoPtr pScrn)
 		       format_integer_base2(READ_SCR(pSmi, i)));
 }
 
-static void
+void
 SMI501_WaitVSync(SMIPtr pSmi, int vsync_count)
 {
     int32_t	status, timeout;
diff --git a/src/smi_501.h b/src/smi_501.h
index ddee5c5..a9c9436 100644
--- a/src/smi_501.h
+++ b/src/smi_501.h
@@ -788,8 +788,31 @@ typedef struct _MSOCRegRec {
 	} f;
 	int32_t		value;
     } crt_vsync;
+
+#define CRT_DETECT			0x080224
+    /*	CRT MONITOR DETECT
+     *	Read/Write MMIO_base + 0x080224
+     *	Power-on Default Undefined
+     *
+     *	0:23	Monitor Detect Data in RGB 8:8:8. This field is read-only.
+     *	24:24	Monitor Detect Enable.
+     *		0: Disable.
+     *		1: Enable.
+     *	25:25	Monitor Detect Read Back.
+     *		1: All R, G, and B voltages are greater than 0.325 V.
+     *		0: All R, G, and B voltages are less than or equal to 0.325 V.
+     */
+    union {
+	struct {
+	    int32_t	data		: bits( 0, 23);
+	    int32_t	enable		: bits(24, 24);
+	    int32_t	voltage		: bits(25, 25);
+	} f;
+	int32_t		value;
+    } crt_detect;
 } MSOCRegRec, *MSOCRegPtr;
 
+
 #define PANEL_PALETTE			0x080400
 #define CRT_PALETTE			0x080c00
 
@@ -806,6 +829,7 @@ double SMI501_FindClock(double clock, int max_divider, Bool has1xclck,
 			       int32_t *x2_divider, int32_t *x2_shift);
 double SMI501_FindPLLClock(double clock, int32_t *m, int32_t *n,
 				  int32_t *xclck);
+void SMI501_WaitVSync(SMIPtr pSmi, int vsync_count);
 
 /* Initialize the CRTC-independent hardware registers */
 Bool SMI501_HWInit(ScrnInfoPtr pScrn);