[Openchrome-devel] HW cursor not working with KMS on K8M890CE

[Ondrej Zary]

Hello,
KMS is working on K8M890CE (Asus P3-AE5 system, M2V-TVM board) except for the
HW cursor. The problem is that KMS code seems to use wrong registers at least
on this chipset:

via_show_cursor():
if (iga->index) {
        VIA_WRITE(HI_FBOFFSET, iga->cursor_kmap.bo->offset);
        VIA_WRITE(HI_CONTROL, 0xB6000005);
} else {
        VIA_WRITE(PRIM_HI_FBOFFSET, iga->cursor_kmap.bo->offset);
        VIA_WRITE(PRIM_HI_CTRL, 0x36000005);
}

iga->index is 0 so PRIM_HI_ regs are used.
But UMS xf86-video-openchrome uses the other register set:

iga1_crtc_show_cursor():
    switch(pVia->Chipset) {
    case VIA_CX700:
    case VIA_P4M890:
    case VIA_P4M900:
    case VIA_VX800:
    case VIA_VX855:
    case VIA_VX900:
        VIASETREG(PRIM_HI_FBOFFSET, iga->cursor_bo->offset);
        VIASETREG(PRIM_HI_CTRL, 0x36000005);
        break;

    default:
        /* Mono Cursor Display Path [bit31]: Primary */
        VIASETREG(HI_FBOFFSET, iga->cursor_bo->offset);
        VIASETREG(HI_CONTROL, 0x76000005);
        break;
    }


Also the values written to control registers are different - KMS uses
0xB6000005 to enable cursor while UMS uses 0x76000005.

The following hack makes HW cursor work on K8M890CE:

diff --git a/drivers/gpu/drm/via/via_crtc.c b/drivers/gpu/drm/via/via_crtc.c
index f7c8a7e..0bb27fb 100644
--- a/drivers/gpu/drm/via/via_crtc.c
+++ b/drivers/gpu/drm/via/via_crtc.c
@@ -52,13 +52,8 @@ via_hide_cursor(struct drm_crtc *crtc)
 	struct drm_via_private *dev_priv = crtc->dev->dev_private;
 	uint32_t temp;
 
-	if (iga->index) {
 		temp = VIA_READ(HI_CONTROL);
 		VIA_WRITE(HI_CONTROL, temp & 0xFFFFFFFA);
-	} else {
-		temp = VIA_READ(PRIM_HI_CTRL);
-		VIA_WRITE(PRIM_HI_CTRL, temp & 0xFFFFFFFA);
-	}
 }
 
 static void
@@ -71,13 +66,8 @@ via_show_cursor(struct drm_crtc *crtc)
 		return;
 
 	/* Program the offset and turn on Hardware icon Cursor */
-	if (iga->index) {
 		VIA_WRITE(HI_FBOFFSET, iga->cursor_kmap.bo->offset);
-		VIA_WRITE(HI_CONTROL, 0xB6000005);
-	} else {
-		VIA_WRITE(PRIM_HI_FBOFFSET, iga->cursor_kmap.bo->offset);
-		VIA_WRITE(PRIM_HI_CTRL, 0x36000005);
-	}
+		VIA_WRITE(HI_CONTROL, 0x76000005);
 }
 
 static int
@@ -153,13 +143,8 @@ via_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
 		ypos = 0;
 	}
 
-	if (iga->index) {
 		VIA_WRITE(HI_POSSTART, ((xpos << 16) | (ypos & 0x07ff)));
 		VIA_WRITE(HI_CENTEROFFSET, ((xoff << 16) | (yoff & 0x07ff)));
-	} else {
-		VIA_WRITE(PRIM_HI_POSSTART, ((xpos << 16) | (ypos & 0x07ff)));
-		VIA_WRITE(PRIM_HI_CENTEROFFSET, ((xoff << 16) | (yoff & 0x07ff)));
-	}
 	return 0;
 }
 


-- 
Ondrej Zary