drm/i915/dvo/ch7xxx: Fix suspend/resume

Poke a few more bits into the ch7xxx to make
it output a picture after being reset during S3.

In particular we need to set the input buffer select (IBS),
and enable VGA vsync output on the BCO pin. Selecting
VGA hsync on the c/h sync pin doesn't actually seem necessary
on my ADD card at least, but the BIOS selects it so why not.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221122120825.26338-2-ville.syrjala@linux.intel.comAcked-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/dvo_ch7xxx.c

@@ -50,15 +50,26 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define CH7xxx_INPUT_CLOCK	0x1d
 #define CH7xxx_GPIO		0x1e
 #define CH7xxx_GPIO_HPIR	(1<<3)
-#define CH7xxx_IDF		0x1f
 
+#define CH7xxx_IDF		0x1f
+#define CH7xxx_IDF_IBS		(1<<7)
+#define CH7xxx_IDF_DES		(1<<6)
 #define CH7xxx_IDF_HSP		(1<<3)
 #define CH7xxx_IDF_VSP		(1<<4)
 
 #define CH7xxx_CONNECTION_DETECT 0x20
 #define CH7xxx_CDET_DVI		(1<<5)
 
-#define CH7301_DAC_CNTL		0x21
+#define CH7xxx_DAC_CNTL		0x21
+#define CH7xxx_SYNCO_MASK	(3 << 3)
+#define CH7xxx_SYNCO_VGA_HSYNC	(1 << 3)
+
+#define CH7xxx_CLOCK_OUTPUT	0x22
+#define CH7xxx_BCOEN		(1 << 4)
+#define CH7xxx_BCOP		(1 << 3)
+#define CH7xxx_BCO_MASK		(7 << 0)
+#define CH7xxx_BCO_VGA_VSYNC	(6 << 0)
+
 #define CH7301_HOTPLUG		0x23
 #define CH7xxx_TCTL		0x31
 #define CH7xxx_TVCO		0x32
@@ -301,6 +312,8 @@ static void ch7xxx_mode_set(struct intel_dvo_device *dvo,
 
 	ch7xxx_readb(dvo, CH7xxx_IDF, &idf);
 
+	idf |= CH7xxx_IDF_IBS;
+
 	idf &= ~(CH7xxx_IDF_HSP | CH7xxx_IDF_VSP);
 	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
 		idf |= CH7xxx_IDF_HSP;
@@ -309,6 +322,11 @@ static void ch7xxx_mode_set(struct intel_dvo_device *dvo,
 		idf |= CH7xxx_IDF_VSP;
 
 	ch7xxx_writeb(dvo, CH7xxx_IDF, idf);
+
+	ch7xxx_writeb(dvo, CH7xxx_DAC_CNTL,
+		      CH7xxx_SYNCO_VGA_HSYNC);
+	ch7xxx_writeb(dvo, CH7xxx_CLOCK_OUTPUT,
+		      CH7xxx_BCOEN | CH7xxx_BCO_VGA_VSYNC);
 }
 
 /* set the CH7xxx power state */