[Intel-gfx] [PATCH 1/3] drm/i915: No panel fitter on 830M or non-mobile gen2/3 platforms

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

PFIT_CONTROL doesn't exist on 830M, so avoid reading it in
i9xx_get_pfit_config().

Also assume that only mobile gen2/3 chipsets have a panel fitter. This
matches the documentation, but I didn't have real hardware to verify.

Gen4 docmentation is a bit inconsistent, but experimenetation on my
LPT machine suggests that the panel fitter is available on non-mobile
gen4 platforms. At least on this machine panel fitter appears works
just fine even on VGA output.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 3 +++
 drivers/gpu/drm/i915/intel_overlay.c | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a51e105..9f8c5b5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5428,6 +5428,9 @@ static void i9xx_get_pfit_config(struct intel_crtc *crtc,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	uint32_t tmp;
 
+	if (INTEL_INFO(dev)->gen <= 3 && (IS_I830(dev) || !IS_MOBILE(dev)))
+		return;
+
 	tmp = I915_READ(PFIT_CONTROL);
 	if (!(tmp & PFIT_ENABLE))
 		return;
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index a1397b1..424f094 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1005,7 +1005,7 @@ static int intel_panel_fitter_pipe(struct drm_device *dev)
 	u32  pfit_control;
 
 	/* i830 doesn't have a panel fitter */
-	if (IS_I830(dev))
+	if (INTEL_INFO(dev)->gen <= 3 && (IS_I830(dev) || !IS_MOBILE(dev)))
 		return -1;
 
 	pfit_control = I915_READ(PFIT_CONTROL);
-- 
1.8.3.2