struct aspeed_gfx_config {
        u32 dac_reg;            /* DAC register in SCU */
+       u32 int_clear_reg;      /* Interrupt clear register */
        u32 vga_scratch_reg;    /* VGA scratch register in SCU */
        u32 throd_val;          /* Default Threshold Seting */
        u32 scan_line_max;      /* Max memory size of one scan line */
 
 static const struct aspeed_gfx_config ast2400_config = {
        .dac_reg = 0x2c,
+       .int_clear_reg = 0x60,
        .vga_scratch_reg = 0x50,
        .throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
        .scan_line_max = 64,
 
 static const struct aspeed_gfx_config ast2500_config = {
        .dac_reg = 0x2c,
+       .int_clear_reg = 0x60,
        .vga_scratch_reg = 0x50,
        .throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
        .scan_line_max = 128,
 
        if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
                drm_crtc_handle_vblank(&priv->pipe.crtc);
-               writel(reg, priv->base + CRT_CTRL1);
+               writel(reg, priv->base + priv->int_clr_reg);
                return IRQ_HANDLED;
        }
 
        config = match->data;
 
        priv->dac_reg = config->dac_reg;
+       priv->int_clr_reg = config->int_clear_reg;
        priv->vga_scratch_reg = config->vga_scratch_reg;
        priv->throd_val = config->throd_val;
        priv->scan_line_max = config->scan_line_max;