If IPC is enabled in BXT, display underruns are observed.
WA: The Line Time programmed in the WM_LINETIME register should be
half of the actual calculated Line Time.
Programmed Line Time = 1/2*Calculated Line Time
Signed-off-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 2 ++
drivers/gpu/drm/i915/i915_drv.h | 3 +++
drivers/gpu/drm/i915/intel_pm.c | 11 +++++++++--
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 445fec9..1b0a589 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1243,6 +1243,8 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
intel_runtime_pm_enable(dev_priv);
+ dev_priv->ipc_enabled = false;
+
/* Everything is in place, we can now relax! */
DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
driver.name, driver.major, driver.minor, driver.patchlevel,
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 63c0ea0..394d7ea 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2128,6 +2128,9 @@ struct drm_i915_private {
/* perform PHY state sanity checks? */
bool chv_phy_assert[2];
+ /* To apply IPC WA */
+ bool ipc_enabled;
+
/* Used to save the pipe-to-encoder mapping for audio */
struct intel_encoder *av_enc_map[I915_MAX_PIPES];
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8908736..7090a7c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3769,7 +3769,10 @@ skl_compute_wm_level(const struct drm_i915_private *dev_priv,
static uint32_t
skl_compute_linetime_wm(struct intel_crtc_state *cstate)
{
+ struct drm_atomic_state *state = cstate->base.state;
+ struct drm_i915_private *dev_priv = to_i915(state->dev);
uint32_t pixel_rate;
+ uint32_t linetime_wm;
if (!cstate->base.active)
return 0;
@@ -3779,8 +3782,12 @@ skl_compute_linetime_wm(struct intel_crtc_state *cstate)
if (WARN_ON(pixel_rate == 0))
return 0;
- return DIV_ROUND_UP(8 * cstate->base.adjusted_mode.crtc_htotal * 1000,
- pixel_rate);
+ linetime_wm = DIV_ROUND_UP(8 * cstate->base.adjusted_mode.crtc_htotal *
+ 1000, pixel_rate);
+ if (IS_BROXTON(dev_priv) && dev_priv->ipc_enabled)
+ linetime_wm = DIV_ROUND_UP(linetime_wm, 2);
+
+ return linetime_wm;
}
static void skl_compute_transition_wm(struct intel_crtc_state *cstate,
--
2.10.1
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