[Intel-gfx] [PATCH] drm/i915: preserve pipe A quirk in i9xx_set_pipeconf

[Daniel Vetter]

This regression has been introduced in

commit 9f11a9e4e50006b615ba94722dfc33ced89664cf
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Thu Jun 13 00:54:58 2013 +0200

    drm/i915: set up PIPECONF explicitly for i9xx/vlv platforms

Ville brough up the idea that this is just the pipe A quirk gone
wrong.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66462
References: https://lkml.org/lkml/2013/8/26/238
Cc: Meelis Roos <mroos at ut.ee>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_display.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f7d868e..be97b42 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4833,7 +4833,11 @@ static void i9xx_set_pipeconf(struct intel_crtc *intel_crtc)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	uint32_t pipeconf;
 
-	pipeconf = 0;
+	if (dev_priv->quirks & QUIRK_PIPEA_FORCE) {
+		pipeconf =
+			I915_READ(PIPECONF(intel_crtc->pipe)) & PIPECONF_ENABLE;
+	} else
+		pipeconf = 0;
 
 	if (intel_crtc->config.double_wide)
 		pipeconf |= PIPECONF_DOUBLE_WIDE;
-- 
1.8.4.rc3