Display Workarounds #1135
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
Changes since V1:
- Add Workaround number in commit & code
Signed-off-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 2 ++
drivers/gpu/drm/i915/i915_drv.h | 2 ++
drivers/gpu/drm/i915/intel_pm.c | 12 ++++++++++--
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 b893e67..f27e4bd 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1251,6 +1251,8 @@ 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 1ec9619..64b0c90 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2306,6 +2306,8 @@ struct drm_i915_private {
/* perform PHY state sanity checks? */
bool chv_phy_assert[2];
+ 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 a467ffe..89d8a28 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3755,7 +3755,10 @@ 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;
@@ -3765,8 +3768,13 @@ 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);
+ /* Display WA #1135 for BXT:All */
+ 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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