From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
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 <paulo.r.zanoni@xxxxxxxxx>
---
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 50ed333..9e55b9b 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;
--
2.1.4
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