[PATCH 2/8] drm/i915: Assert that runtime pm is active on user fw access

Mika Kuoppala
2014-12-08T18:24:31Z

From: Chris Wilson <chris@chris-wilson.co.uk>

On user forcewake access, assert that runtime pm reference is held.
Fix and cleanup the callsites accordingly.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 2 +
drivers/gpu/drm/i915/intel_display.c | 19 +--------
drivers/gpu/drm/i915/intel_lrc.c | 53 ++-----------------------
drivers/gpu/drm/i915/intel_uncore.c | 76 ++++++++++++------------------------
4 files changed, 31 insertions(+), 119 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index d0e445e..e142629 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4250,6 +4250,7 @@ static int i915_forcewake_open(struct inode *inode, struct file *file)
if (INTEL_INFO(dev)->gen < 6)
return 0;

+ intel_runtime_pm_get(dev_priv);
gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);

return 0;
@@ -4264,6 +4265,7 @@ static int i915_forcewake_release(struct inode *inode, struct file *file)
return 0;

gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
+ intel_runtime_pm_put(dev_priv);

return 0;
}
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d5153a4..86c2885 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7862,19 +7862,8 @@ static void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
/*
* Make sure we're not on PC8 state before disabling PC8, otherwise
* we'll hang the machine. To prevent PC8 state, just enable force_wake.
- *
- * The other problem is that hsw_restore_lcpll() is called as part of
- * the runtime PM resume sequence, so we can't just call
- * gen6_gt_force_wake_get() because that function calls
- * intel_runtime_pm_get(), and we can't change the runtime PM refcount
- * while we are on the resume sequence. So to solve this problem we have
- * to call special forcewake code that doesn't touch runtime PM and
- * doesn't enable the forcewake delayed work.
*/
- spin_lock_irq(&dev_priv->uncore.lock);
- if (dev_priv->uncore.forcewake_count++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv, FORCEWAKE_ALL);
- spin_unlock_irq(&dev_priv->uncore.lock);
+ gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);

if (val & LCPLL_POWER_DOWN_ALLOW) {
val &= ~LCPLL_POWER_DOWN_ALLOW;
@@ -7904,11 +7893,7 @@ static void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
DRM_ERROR("Switching back to LCPLL failed\n");
}

- /* See the big comment above. */
- spin_lock_irq(&dev_priv->uncore.lock);
- if (--dev_priv->uncore.forcewake_count == 0)
- dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
- spin_unlock_irq(&dev_priv->uncore.lock);
+ gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
}

/*
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index a82020e..fcb5140 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -284,7 +284,6 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
struct drm_i915_private *dev_priv = dev->dev_private;
uint64_t temp = 0;
uint32_t desc[4];
- unsigned long flags;

/* XXX: You must always write both descriptors in the order below. */
if (ctx_obj1)
@@ -298,63 +297,17 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
desc[3] = (u32)(temp >> 32);
desc[2] = (u32)temp;

- /* Set Force Wakeup bit to prevent GT from entering C6 while ELSP writes
- * are in progress.
- *
- * The other problem is that we can't just call gen6_gt_force_wake_get()
- * because that function calls intel_runtime_pm_get(), which might sleep.
- * Instead, we do the runtime_pm_get/put when creating/destroying requests.
- */
- spin_lock_irqsave(&dev_priv->uncore.lock, flags);
- if (IS_CHERRYVIEW(dev) || INTEL_INFO(dev)->gen >= 9) {
- if (dev_priv->uncore.fw_rendercount++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv,
- FORCEWAKE_RENDER);
- if (dev_priv->uncore.fw_mediacount++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv,
- FORCEWAKE_MEDIA);
- if (INTEL_INFO(dev)->gen >= 9) {
- if (dev_priv->uncore.fw_blittercount++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv,
- FORCEWAKE_BLITTER);
- }
- } else {
- if (dev_priv->uncore.forcewake_count++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv,
- FORCEWAKE_ALL);
- }
- spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
-
+ gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
I915_WRITE(RING_ELSP(ring), desc[1]);
I915_WRITE(RING_ELSP(ring), desc[0]);
I915_WRITE(RING_ELSP(ring), desc[3]);
+
/* The context is automatically loaded after the following */
I915_WRITE(RING_ELSP(ring), desc[2]);

/* ELSP is a wo register, so use another nearby reg for posting instead */
POSTING_READ(RING_EXECLIST_STATUS(ring));
-
- /* Release Force Wakeup (see the big comment above). */
- spin_lock_irqsave(&dev_priv->uncore.lock, flags);
- if (IS_CHERRYVIEW(dev) || INTEL_INFO(dev)->gen >= 9) {
- if (--dev_priv->uncore.fw_rendercount == 0)
- dev_priv->uncore.funcs.force_wake_put(dev_priv,
- FORCEWAKE_RENDER);
- if (--dev_priv->uncore.fw_mediacount == 0)
- dev_priv->uncore.funcs.force_wake_put(dev_priv,
- FORCEWAKE_MEDIA);
- if (INTEL_INFO(dev)->gen >= 9) {
- if (--dev_priv->uncore.fw_blittercount == 0)
- dev_priv->uncore.funcs.force_wake_put(dev_priv,
- FORCEWAKE_BLITTER);
- }
- } else {
- if (--dev_priv->uncore.forcewake_count == 0)
- dev_priv->uncore.funcs.force_wake_put(dev_priv,
- FORCEWAKE_ALL);
- }
-
- spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
+ gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
}

static int execlists_update_context(struct drm_i915_gem_object *ctx_obj,
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 38ac389..a1ceb92 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -24,6 +24,8 @@
#include "i915_drv.h"
#include "intel_drv.h"

+#include <linux/pm_runtime.h>
+
#define FORCEWAKE_ACK_TIMEOUT_MS 2

#define __raw_i915_read8(dev_priv__, reg__) readb((dev_priv__)->regs + (reg__))
@@ -247,10 +249,6 @@ static void __vlv_force_wake_put(struct drm_i915_private *dev_priv,

static void vlv_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)
{
- unsigned long irqflags;
-
- spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
-
if (fw_engine & FORCEWAKE_RENDER &&
dev_priv->uncore.fw_rendercount++ != 0)
fw_engine &= ~FORCEWAKE_RENDER;
@@ -260,16 +258,10 @@ static void vlv_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)

if (fw_engine)
dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_engine);
-
- spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
}

static void vlv_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
{
- unsigned long irqflags;
-
- spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
-
if (fw_engine & FORCEWAKE_RENDER) {
WARN_ON(!dev_priv->uncore.fw_rendercount);
if (--dev_priv->uncore.fw_rendercount != 0)
@@ -284,8 +276,6 @@ static void vlv_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)

if (fw_engine)
dev_priv->uncore.funcs.force_wake_put(dev_priv, fw_engine);
-
- spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
}

static void __gen9_gt_force_wake_mt_reset(struct drm_i915_private *dev_priv)
@@ -380,10 +370,6 @@ __gen9_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
static void
gen9_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)
{
- unsigned long irqflags;
-
- spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
-
if (FORCEWAKE_RENDER & fw_engine) {
if (dev_priv->uncore.fw_rendercount++ == 0)
dev_priv->uncore.funcs.force_wake_get(dev_priv,
@@ -401,17 +387,11 @@ gen9_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)
dev_priv->uncore.funcs.force_wake_get(dev_priv,
FORCEWAKE_BLITTER);
}
-
- spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
}

static void
gen9_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
{
- unsigned long irqflags;
-
- spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
-
if (FORCEWAKE_RENDER & fw_engine) {
WARN_ON(dev_priv->uncore.fw_rendercount == 0);
if (--dev_priv->uncore.fw_rendercount == 0)
@@ -432,8 +412,6 @@ gen9_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
dev_priv->uncore.funcs.force_wake_put(dev_priv,
FORCEWAKE_BLITTER);
}
-
- spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
}

static void gen6_force_wake_timer(unsigned long arg)
@@ -564,17 +542,20 @@ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)

intel_runtime_pm_get(dev_priv);

- /* Redirect to Gen9 specific routine */
- if (IS_GEN9(dev_priv->dev))
- return gen9_force_wake_get(dev_priv, fw_engine);
-
- /* Redirect to VLV specific routine */
- if (IS_VALLEYVIEW(dev_priv->dev))
- return vlv_force_wake_get(dev_priv, fw_engine);
+ WARN_ON(!pm_runtime_active(&dev_priv->dev->pdev->dev));

spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
- if (dev_priv->uncore.forcewake_count++ == 0)
- dev_priv->uncore.funcs.force_wake_get(dev_priv, FORCEWAKE_ALL);
+
+ if (IS_GEN9(dev_priv->dev)) {
+ gen9_force_wake_get(dev_priv, fw_engine);
+ } else if (IS_VALLEYVIEW(dev_priv->dev)) {
+ vlv_force_wake_get(dev_priv, fw_engine);
+ } else {
+ if (dev_priv->uncore.forcewake_count++ == 0)
+ dev_priv->uncore.funcs.force_wake_get(dev_priv,
+ FORCEWAKE_ALL);
+ }
+
spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
}

@@ -588,31 +569,22 @@ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
if (!dev_priv->uncore.funcs.force_wake_put)
return;

- /* Redirect to Gen9 specific routine */
+ spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+
if (IS_GEN9(dev_priv->dev)) {
gen9_force_wake_put(dev_priv, fw_engine);
- goto out;
- }
-
- /* Redirect to VLV specific routine */
- if (IS_VALLEYVIEW(dev_priv->dev)) {
+ } else if (IS_VALLEYVIEW(dev_priv->dev)) {
vlv_force_wake_put(dev_priv, fw_engine);
- goto out;
- }
-
- spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
- WARN_ON(!dev_priv->uncore.forcewake_count);
-
- if (--dev_priv->uncore.forcewake_count == 0) {
- dev_priv->uncore.forcewake_count++;
- mod_timer_pinned(&dev_priv->uncore.force_wake_timer,
- jiffies + 1);
+ } else {
+ WARN_ON(!dev_priv->uncore.forcewake_count);
+ if (--dev_priv->uncore.forcewake_count == 0) {
+ dev_priv->uncore.forcewake_count++;
+ mod_timer_pinned(&dev_priv->uncore.force_wake_timer,
+ jiffies + 1);
+ }
}

spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
-
-out:
- intel_runtime_pm_put(dev_priv);
}

void assert_force_wake_inactive(struct drm_i915_private *dev_priv)
--
1.9.1