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drm/i915: Fixup cursor latency used for IVB lp3 watermarks
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It operates at twice the declared latency, so adjust the computation to
avoid potential flicker at low power.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50248
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Chris Wilson authored and Daniel Vetter committed Dec 17, 2012
1 parent 2065209 commit c43d018
Showing 1 changed file with 112 additions and 5 deletions.
117 changes: 112 additions & 5 deletions drivers/gpu/drm/i915/intel_pm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1811,8 +1811,110 @@ static void sandybridge_update_wm(struct drm_device *dev)
enabled |= 2;
}

if ((dev_priv->num_pipe == 3) &&
g4x_compute_wm0(dev, 2,
/*
* Calculate and update the self-refresh watermark only when one
* display plane is used.
*
* SNB support 3 levels of watermark.
*
* WM1/WM2/WM2 watermarks have to be enabled in the ascending order,
* and disabled in the descending order
*
*/
I915_WRITE(WM3_LP_ILK, 0);
I915_WRITE(WM2_LP_ILK, 0);
I915_WRITE(WM1_LP_ILK, 0);

if (!single_plane_enabled(enabled) ||
dev_priv->sprite_scaling_enabled)
return;
enabled = ffs(enabled) - 1;

/* WM1 */
if (!ironlake_compute_srwm(dev, 1, enabled,
SNB_READ_WM1_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;

I915_WRITE(WM1_LP_ILK,
WM1_LP_SR_EN |
(SNB_READ_WM1_LATENCY() << WM1_LP_LATENCY_SHIFT) |
(fbc_wm << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);

/* WM2 */
if (!ironlake_compute_srwm(dev, 2, enabled,
SNB_READ_WM2_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;

I915_WRITE(WM2_LP_ILK,
WM2_LP_EN |
(SNB_READ_WM2_LATENCY() << WM1_LP_LATENCY_SHIFT) |
(fbc_wm << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);

/* WM3 */
if (!ironlake_compute_srwm(dev, 3, enabled,
SNB_READ_WM3_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
return;

I915_WRITE(WM3_LP_ILK,
WM3_LP_EN |
(SNB_READ_WM3_LATENCY() << WM1_LP_LATENCY_SHIFT) |
(fbc_wm << WM1_LP_FBC_SHIFT) |
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);
}

static void ivybridge_update_wm(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int latency = SNB_READ_WM0_LATENCY() * 100; /* In unit 0.1us */
u32 val;
int fbc_wm, plane_wm, cursor_wm;
int ignore_fbc_wm, ignore_plane_wm, ignore_cursor_wm;
unsigned int enabled;

enabled = 0;
if (g4x_compute_wm0(dev, 0,
&sandybridge_display_wm_info, latency,
&sandybridge_cursor_wm_info, latency,
&plane_wm, &cursor_wm)) {
val = I915_READ(WM0_PIPEA_ILK);
val &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
I915_WRITE(WM0_PIPEA_ILK, val |
((plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm));
DRM_DEBUG_KMS("FIFO watermarks For pipe A -"
" plane %d, " "cursor: %d\n",
plane_wm, cursor_wm);
enabled |= 1;
}

if (g4x_compute_wm0(dev, 1,
&sandybridge_display_wm_info, latency,
&sandybridge_cursor_wm_info, latency,
&plane_wm, &cursor_wm)) {
val = I915_READ(WM0_PIPEB_ILK);
val &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
I915_WRITE(WM0_PIPEB_ILK, val |
((plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm));
DRM_DEBUG_KMS("FIFO watermarks For pipe B -"
" plane %d, cursor: %d\n",
plane_wm, cursor_wm);
enabled |= 2;
}

if (g4x_compute_wm0(dev, 2,
&sandybridge_display_wm_info, latency,
&sandybridge_cursor_wm_info, latency,
&plane_wm, &cursor_wm)) {
Expand Down Expand Up @@ -1875,12 +1977,17 @@ static void sandybridge_update_wm(struct drm_device *dev)
(plane_wm << WM1_LP_SR_SHIFT) |
cursor_wm);

/* WM3 */
/* WM3, note we have to correct the cursor latency */
if (!ironlake_compute_srwm(dev, 3, enabled,
SNB_READ_WM3_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&fbc_wm, &plane_wm, &cursor_wm))
&fbc_wm, &plane_wm, &ignore_cursor_wm) ||
!ironlake_compute_srwm(dev, 3, enabled,
2 * SNB_READ_WM3_LATENCY() * 500,
&sandybridge_display_srwm_info,
&sandybridge_cursor_srwm_info,
&ignore_fbc_wm, &ignore_plane_wm, &cursor_wm))
return;

I915_WRITE(WM3_LP_ILK,
Expand Down Expand Up @@ -4005,7 +4112,7 @@ void intel_init_pm(struct drm_device *dev)
} else if (IS_IVYBRIDGE(dev)) {
/* FIXME: detect B0+ stepping and use auto training */
if (SNB_READ_WM0_LATENCY()) {
dev_priv->display.update_wm = sandybridge_update_wm;
dev_priv->display.update_wm = ivybridge_update_wm;
dev_priv->display.update_sprite_wm = sandybridge_update_sprite_wm;
} else {
DRM_DEBUG_KMS("Failed to read display plane latency. "
Expand Down

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