From ce65e47b78789b4f78be1fd7e4c884df74a9f075 Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Tue, 30 Jun 2015 10:53:05 -0300 Subject: [PATCH] drm/i915: don't increment the FBC threshold at fbc_enable We first set the threshold value when we're allocating the CFB, and then later at {ilk,gen7}_fbc_enable() we increment it in case we're using 16bpp. While that is correct, it is dangerous: if we rework the code a little bit in a way that allows us to call intel_fbc_enable() without necessarily calling i915_gem_stolen_setup_compression() first, we might end up incrementing threshold more than once. To prevent that, increment a temporary variable instead. v2: Rebase. Signed-off-by: Paulo Zanoni Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_fbc.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c index 50ed3332def1..9e55b9badb4b 100644 --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -188,14 +188,15 @@ static void ilk_fbc_enable(struct drm_crtc *crtc) struct drm_i915_gem_object *obj = intel_fb_obj(fb); struct intel_crtc *intel_crtc = to_intel_crtc(crtc); u32 dpfc_ctl; + int threshold = dev_priv->fbc.threshold; dev_priv->fbc.enabled = true; dpfc_ctl = DPFC_CTL_PLANE(intel_crtc->plane); if (drm_format_plane_cpp(fb->pixel_format, 0) == 2) - dev_priv->fbc.threshold++; + threshold++; - switch (dev_priv->fbc.threshold) { + switch (threshold) { case 4: case 3: dpfc_ctl |= DPFC_CTL_LIMIT_4X; @@ -259,6 +260,7 @@ static void gen7_fbc_enable(struct drm_crtc *crtc) struct drm_i915_gem_object *obj = intel_fb_obj(fb); struct intel_crtc *intel_crtc = to_intel_crtc(crtc); u32 dpfc_ctl; + int threshold = dev_priv->fbc.threshold; dev_priv->fbc.enabled = true; @@ -267,9 +269,9 @@ static void gen7_fbc_enable(struct drm_crtc *crtc) dpfc_ctl |= IVB_DPFC_CTL_PLANE(intel_crtc->plane); if (drm_format_plane_cpp(fb->pixel_format, 0) == 2) - dev_priv->fbc.threshold++; + threshold++; - switch (dev_priv->fbc.threshold) { + switch (threshold) { case 4: case 3: dpfc_ctl |= DPFC_CTL_LIMIT_4X; -- 2.20.1