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drm/i915: add multi-threaded forcewake support
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On IVB C0+ with newer BIOSes, the forcewake handshake has changed.  There's
now a bitfield for different driver components to keep the GT powered
on.  On Linux, we centralize forcewake handling in one place, so we
still just need a single bit, but we need to use the new registers if MT
forcewake is enabled.

This needs testing on affected machines.  Please reply with your
tested-by if you had problems after a BIOS upgrade and this patch fixes
them.

v2: force MT mode. shift by 16
v3: set MT force wake bits then check ECOBUS

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=42923
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Tested-by: Robert Hooker <robert.hooker@canonical.com>
Tested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
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Keith Packard committed Nov 23, 2011
1 parent f10cdea commit 8d715f0
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Showing 4 changed files with 66 additions and 8 deletions.
35 changes: 29 additions & 6 deletions drivers/gpu/drm/i915/i915_drv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -328,7 +328,7 @@ void intel_detect_pch(struct drm_device *dev)
}
}

static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
{
int count;

Expand All @@ -344,6 +344,22 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
udelay(10);
}

void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
{
int count;

count = 0;
while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_MT_ACK) & 1))
udelay(10);

I915_WRITE_NOTRACE(FORCEWAKE_MT, (1<<16) | 1);
POSTING_READ(FORCEWAKE_MT);

count = 0;
while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_MT_ACK) & 1) == 0)
udelay(10);
}

/*
* Generally this is called implicitly by the register read function. However,
* if some sequence requires the GT to not power down then this function should
Expand All @@ -356,15 +372,21 @@ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)

/* Forcewake is atomic in case we get in here without the lock */
if (atomic_add_return(1, &dev_priv->forcewake_count) == 1)
__gen6_gt_force_wake_get(dev_priv);
dev_priv->display.force_wake_get(dev_priv);
}

static void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
{
I915_WRITE_NOTRACE(FORCEWAKE, 0);
POSTING_READ(FORCEWAKE);
}

void __gen6_gt_force_wake_mt_put(struct drm_i915_private *dev_priv)
{
I915_WRITE_NOTRACE(FORCEWAKE_MT, (1<<16) | 0);
POSTING_READ(FORCEWAKE_MT);
}

/*
* see gen6_gt_force_wake_get()
*/
Expand All @@ -373,7 +395,7 @@ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));

if (atomic_dec_and_test(&dev_priv->forcewake_count))
__gen6_gt_force_wake_put(dev_priv);
dev_priv->display.force_wake_put(dev_priv);
}

void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
Expand Down Expand Up @@ -903,8 +925,9 @@ MODULE_LICENSE("GPL and additional rights");
/* We give fast paths for the really cool registers */
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
(((dev_priv)->info->gen >= 6) && \
((reg) < 0x40000) && \
((reg) != FORCEWAKE))
((reg) < 0x40000) && \
((reg) != FORCEWAKE) && \
((reg) != ECOBUS))

#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
Expand Down
13 changes: 11 additions & 2 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -107,6 +107,7 @@ struct opregion_header;
struct opregion_acpi;
struct opregion_swsci;
struct opregion_asle;
struct drm_i915_private;

struct intel_opregion {
struct opregion_header *header;
Expand Down Expand Up @@ -221,6 +222,8 @@ struct drm_i915_display_funcs {
struct drm_i915_gem_object *obj);
int (*update_plane)(struct drm_crtc *crtc, struct drm_framebuffer *fb,
int x, int y);
void (*force_wake_get)(struct drm_i915_private *dev_priv);
void (*force_wake_put)(struct drm_i915_private *dev_priv);
/* clock updates for mode set */
/* cursor updates */
/* render clock increase/decrease */
Expand Down Expand Up @@ -1308,6 +1311,11 @@ extern void gen6_set_rps(struct drm_device *dev, u8 val);
extern void intel_detect_pch(struct drm_device *dev);
extern int intel_trans_dp_port_sel(struct drm_crtc *crtc);

extern void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv);
extern void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv);
extern void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv);
extern void __gen6_gt_force_wake_mt_put(struct drm_i915_private *dev_priv);

/* overlay */
#ifdef CONFIG_DEBUG_FS
extern struct intel_overlay_error_state *intel_overlay_capture_error_state(struct drm_device *dev);
Expand Down Expand Up @@ -1352,8 +1360,9 @@ void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);
/* We give fast paths for the really cool registers */
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
(((dev_priv)->info->gen >= 6) && \
((reg) < 0x40000) && \
((reg) != FORCEWAKE))
((reg) < 0x40000) && \
((reg) != FORCEWAKE) && \
((reg) != ECOBUS))

#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg);
Expand Down
4 changes: 4 additions & 0 deletions drivers/gpu/drm/i915/i915_reg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3449,6 +3449,10 @@

#define FORCEWAKE 0xA18C
#define FORCEWAKE_ACK 0x130090
#define FORCEWAKE_MT 0xa188 /* multi-threaded */
#define FORCEWAKE_MT_ACK 0x130040
#define ECOBUS 0xa180
#define FORCEWAKE_MT_ENABLE (1<<5)

#define GT_FIFO_FREE_ENTRIES 0x120008
#define GT_FIFO_NUM_RESERVED_ENTRIES 20
Expand Down
22 changes: 22 additions & 0 deletions drivers/gpu/drm/i915/intel_display.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8491,6 +8491,28 @@ static void intel_init_display(struct drm_device *dev)

/* For FIFO watermark updates */
if (HAS_PCH_SPLIT(dev)) {
dev_priv->display.force_wake_get = __gen6_gt_force_wake_get;
dev_priv->display.force_wake_put = __gen6_gt_force_wake_put;

/* IVB configs may use multi-threaded forcewake */
if (IS_IVYBRIDGE(dev)) {
u32 ecobus;

mutex_lock(&dev->struct_mutex);
__gen6_gt_force_wake_mt_get(dev_priv);
ecobus = I915_READ(ECOBUS);
__gen6_gt_force_wake_mt_put(dev_priv);
mutex_unlock(&dev->struct_mutex);

if (ecobus & FORCEWAKE_MT_ENABLE) {
DRM_DEBUG_KMS("Using MT version of forcewake\n");
dev_priv->display.force_wake_get =
__gen6_gt_force_wake_mt_get;
dev_priv->display.force_wake_put =
__gen6_gt_force_wake_mt_put;
}
}

if (HAS_PCH_IBX(dev))
dev_priv->display.init_pch_clock_gating = ibx_init_clock_gating;
else if (HAS_PCH_CPT(dev))
Expand Down

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