drm/i915: disable VGA plane reliably
This does VGA disable like DDX driver. SR01 bit 5 should be set
before VGA plane disable through control register, otherwise we
might get random crash and lockups.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a58bfad..b06364e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -998,6 +998,29 @@
return 0;
}
+/* Disable the VGA plane that we never use */
+static void i915_disable_vga (struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ u8 sr1;
+ u32 vga_reg;
+
+ if (IS_IGDNG(dev))
+ vga_reg = CPU_VGACNTRL;
+ else
+ vga_reg = VGACNTRL;
+
+ if (I915_READ(vga_reg) & VGA_DISP_DISABLE)
+ return;
+
+ I915_WRITE8(VGA_SR_INDEX, 1);
+ sr1 = I915_READ8(VGA_SR_DATA);
+ I915_WRITE8(VGA_SR_DATA, sr1 | (1 << 5));
+ udelay(100);
+
+ I915_WRITE(vga_reg, VGA_DISP_DISABLE);
+}
+
static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
{
struct drm_device *dev = crtc->dev;
@@ -1200,8 +1223,7 @@
case DRM_MODE_DPMS_OFF:
DRM_DEBUG("crtc %d dpms off\n", pipe);
- /* Disable the VGA plane that we never use */
- I915_WRITE(CPU_VGACNTRL, VGA_DISP_DISABLE);
+ i915_disable_vga(dev);
/* Disable display plane */
temp = I915_READ(dspcntr_reg);
@@ -1342,7 +1364,7 @@
//intel_crtc_dpms_video(crtc, FALSE); TODO
/* Disable the VGA plane that we never use */
- I915_WRITE(VGACNTRL, VGA_DISP_DISABLE);
+ i915_disable_vga(dev);
/* Disable display plane */
temp = I915_READ(dspcntr_reg);