From 61bc95c1fbbb6a08b55bbe161fdf1ea5493fc595 Mon Sep 17 00:00:00 2001 From: Egbert Eich Date: Mon, 4 Mar 2013 09:24:38 -0500 Subject: [PATCH] DRM/i915: On G45 enable cursor plane briefly after enabling the display plane. On G45 some low res modes (800x600 and 1024x768) produce a blank screen when the display plane is enabled with with cursor plane off. Experiments showed that this issue occurred when the following conditions were met: a. a previous mode had the cursor plane enabled (Xserver). b. this mode or the previous one was using self refresh. (Thus the problem was only seen with low res modes). The screens lit up as soon as the cursor plane got enabled. Therefore the blank screen occurred only in console mode, not when running an Xserver. It also seemed to be necessary to disable self refresh while briefly enabling the cursor plane. Signed-off-by: Egbert Eich Bugzilla: https://bugs.freedesktop.org/attachment.cgi?bugid=61457 Acked-by: Chris Wilson [danvet: drop spurious whitespace change.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 09659ff6d24d..0a02e044b653 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3604,6 +3604,30 @@ static void intel_crtc_dpms_overlay(struct intel_crtc *intel_crtc, bool enable) */ } +/** + * i9xx_fixup_plane - ugly workaround for G45 to fire up the hardware + * cursor plane briefly if not already running after enabling the display + * plane. + * This workaround avoids occasional blank screens when self refresh is + * enabled. + */ +static void +g4x_fixup_plane(struct drm_i915_private *dev_priv, enum pipe pipe) +{ + u32 cntl = I915_READ(CURCNTR(pipe)); + + if ((cntl & CURSOR_MODE) == 0) { + u32 fw_bcl_self = I915_READ(FW_BLC_SELF); + + I915_WRITE(FW_BLC_SELF, fw_bcl_self & ~FW_BLC_SELF_EN); + I915_WRITE(CURCNTR(pipe), CURSOR_MODE_64_ARGB_AX); + intel_wait_for_vblank(dev_priv->dev, pipe); + I915_WRITE(CURCNTR(pipe), cntl); + I915_WRITE(CURBASE(pipe), I915_READ(CURBASE(pipe))); + I915_WRITE(FW_BLC_SELF, fw_bcl_self); + } +} + static void i9xx_crtc_enable(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; @@ -3629,6 +3653,8 @@ static void i9xx_crtc_enable(struct drm_crtc *crtc) intel_enable_pipe(dev_priv, pipe, false); intel_enable_plane(dev_priv, plane, pipe); + if (IS_G4X(dev)) + g4x_fixup_plane(dev_priv, pipe); intel_crtc_load_lut(crtc); intel_update_fbc(dev);