drm/mgag200: Enable MGA mode during device register initialization

MGA cards can run in traditional VGA mode or an enhanced MGA mode; with
the latter being required for KMS. So far, MGA mode was enabled during
modesetting. As it's fundamental for device operation, the patch moves
it next to the device register setup.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200730102844.10995-5-tzimmermann@suse.de

drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -61,6 +61,7 @@ static int mgag200_regs_init(struct mga_device *mdev)
 {
 	struct drm_device *dev = &mdev->base;
 	u32 option, option2;
+	u8 crtcext3;
 
 	switch (mdev->type) {
 	case G200_SE_A:
@@ -107,6 +108,10 @@ static int mgag200_regs_init(struct mga_device *mdev)
 	if (mdev->rmmio == NULL)
 		return -ENOMEM;
 
+	RREG_ECRT(0x03, crtcext3);
+	crtcext3 |= MGAREG_CRTCEXT3_MGAMODE;
+	WREG_ECRT(0x03, crtcext3);
+
 	return 0;
 }
 

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -946,7 +946,7 @@ static void mgag200_set_dac_regs(struct mga_device *mdev)
 
 static void mgag200_init_regs(struct mga_device *mdev)
 {
-	u8 crtc11, crtcext3, crtcext4, misc;
+	u8 crtc11, crtcext4, misc;
 
 	mgag200_set_dac_regs(mdev);
 
@@ -961,12 +961,8 @@ static void mgag200_init_regs(struct mga_device *mdev)
 	WREG_CRT(14, 0);
 	WREG_CRT(15, 0);
 
-	RREG_ECRT(0x03, crtcext3);
-
-	crtcext3 |= BIT(7); /* enable MGA mode */
 	crtcext4 = 0x00;
 
-	WREG_ECRT(0x03, crtcext3);
 	WREG_ECRT(0x04, crtcext4);
 
 	RREG_CRT(0x11, crtc11);

drivers/gpu/drm/mgag200/mgag200_reg.h

@@ -256,6 +256,8 @@
 #define MGAREG_CRTCEXT1_VSYNCOFF	BIT(5)
 #define MGAREG_CRTCEXT1_HSYNCOFF	BIT(4)
 
+#define MGAREG_CRTCEXT3_MGAMODE		BIT(7)
+
 /* Cursor X and Y position */
 #define MGA_CURPOSXL 0x3c0c
 #define MGA_CURPOSXH 0x3c0d