From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Currently, calling intel_fbc_enabled() will trigger a register read.
And we call it a lot of times, even when FBC is disabled, so saving a
few cycles would be a good thing.
Another reason for this patch is because we currently call
intel_fbc_enabled() while the HW is runtime suspended, so the read
makes no sense and triggers a WARN. This happens even if FBC is
disabled by default. Of course one could argue that we just shouldn't
be calling intel_fbc_enabled() while the driver is runtime suspended,
and I agree that's a good argument, but I still think that the reason
explained in the first paragraph already justifies the patch.
This problem can easily be reproduced with many subtests of
igt/pm_rpm, and it is a regression introduced by:
commit c5ad011d7d256ecbe173324029e992817194d2b0
Author: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Date: Mon Aug 4 03:51:38 2014 -0700
drm/i915: FBC flush nuke for BDW
Testcase: igt/pm_rpm/cursor (and others)
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 4 ++++
drivers/gpu/drm/i915/intel_pm.c | 31 ++++++++++++++++++++-----------
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5fce16c..999bd57 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -662,6 +662,10 @@ struct i915_fbc {
bool false_color;
+ /* Tracks whether the HW is actually enabled, not whether the feature is
+ * possible. */
+ bool enabled;
+
struct intel_fbc_work {
struct delayed_work work;
struct drm_crtc *crtc;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2ca9fdb..6b41620 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -71,6 +71,8 @@ static void i8xx_disable_fbc(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
u32 fbc_ctl;
+ dev_priv->fbc.enabled = false;
+
/* Disable compression */
fbc_ctl = I915_READ(FBC_CONTROL);
if ((fbc_ctl & FBC_CTL_EN) == 0)
@@ -99,6 +101,8 @@ static void i8xx_enable_fbc(struct drm_crtc *crtc)
int i;
u32 fbc_ctl;
+ dev_priv->fbc.enabled = true;
+
cfb_pitch = dev_priv->fbc.size / FBC_LL_SIZE;
if (fb->pitches[0] < cfb_pitch)
cfb_pitch = fb->pitches[0];
@@ -153,6 +157,8 @@ static void g4x_enable_fbc(struct drm_crtc *crtc)
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
u32 dpfc_ctl;
+ dev_priv->fbc.enabled = true;
+
dpfc_ctl = DPFC_CTL_PLANE(intel_crtc->plane) | DPFC_SR_EN;
if (drm_format_plane_cpp(fb->pixel_format, 0) == 2)
dpfc_ctl |= DPFC_CTL_LIMIT_2X;
@@ -173,6 +179,8 @@ static void g4x_disable_fbc(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
u32 dpfc_ctl;
+ dev_priv->fbc.enabled = false;
+
/* Disable compression */
dpfc_ctl = I915_READ(DPFC_CONTROL);
if (dpfc_ctl & DPFC_CTL_EN) {
@@ -224,6 +232,8 @@ static void ironlake_enable_fbc(struct drm_crtc *crtc)
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
u32 dpfc_ctl;
+ 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++;
@@ -264,6 +274,8 @@ static void ironlake_disable_fbc(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
u32 dpfc_ctl;
+ dev_priv->fbc.enabled = false;
+
/* Disable compression */
dpfc_ctl = I915_READ(ILK_DPFC_CONTROL);
if (dpfc_ctl & DPFC_CTL_EN) {
@@ -290,6 +302,8 @@ static void gen7_enable_fbc(struct drm_crtc *crtc)
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
u32 dpfc_ctl;
+ dev_priv->fbc.enabled = true;
+
dpfc_ctl = IVB_DPFC_CTL_PLANE(intel_crtc->plane);
if (drm_format_plane_cpp(fb->pixel_format, 0) == 2)
dev_priv->fbc.threshold++;
@@ -339,16 +353,7 @@ bool intel_fbc_enabled(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
- /* If it wasn't never enabled by kernel parameter or platform default
- * we can avoid reading registers so many times in vain
- */
- if (!i915.enable_fbc)
- return false;
-
- if (!dev_priv->display.fbc_enabled)
- return false;
-
- return dev_priv->display.fbc_enabled(dev);
+ return dev_priv->fbc.enabled;
}
void gen8_fbc_sw_flush(struct drm_device *dev, u32 value)
@@ -7360,8 +7365,10 @@ void intel_fini_runtime_pm(struct drm_i915_private *dev_priv)
static void intel_init_fbc(struct drm_i915_private *dev_priv)
{
- if (!HAS_FBC(dev_priv))
+ if (!HAS_FBC(dev_priv)) {
+ dev_priv->fbc.enabled = false;
return;
+ }
if (INTEL_INFO(dev_priv)->gen >= 7) {
dev_priv->display.fbc_enabled = ironlake_fbc_enabled;
@@ -7383,6 +7390,8 @@ static void intel_init_fbc(struct drm_i915_private *dev_priv)
/* This value was pulled out of someone's hat */
I915_WRITE(FBC_CONTROL, 500 << FBC_CTL_INTERVAL_SHIFT);
}
+
+ dev_priv->fbc.enabled = dev_priv->display.fbc_enabled(dev_priv->dev);
}
/* Set up chip specific power management-related functions */
--
2.1.0
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