In Geminilake, a FIFO underrun happens the first time a pipe scaler is
enabled after boot/resume from suspend. Disabling DPF clock gating in
the respective CLKGATE_DIS_PSL register prior to enabling the scaler
works around the issue.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 8 ++++++++
drivers/gpu/drm/i915/intel_display.c | 17 +++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 524fdfd..3157c39 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3424,6 +3424,14 @@ enum {
#define PWM2_GATING_DIS (1 << 14)
#define PWM1_GATING_DIS (1 << 13)
+#define _CLKGATE_DIS_PSL_A 0x46520
+#define _CLKGATE_DIS_PSL_B 0x46524
+#define _CLKGATE_DIS_PSL_C 0x46528
+#define DPF_GATING_DIS (1 << 10)
+
+#define CLKGATE_DIS_PSL(pipe) \
+ _MMIO_PIPE(pipe, _CLKGATE_DIS_PSL_A, _CLKGATE_DIS_PSL_B)
+
/*
* Display engine regs
*/
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 85b9e2f5..c24acdd 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3176,6 +3176,7 @@ static void skl_detach_scaler(struct intel_crtc *intel_crtc, int id)
static void skl_detach_scalers(struct intel_crtc *intel_crtc)
{
struct intel_crtc_scaler_state *scaler_state;
+ struct drm_i915_private *dev_priv = to_i915(intel_crtc->base.dev);
int i;
scaler_state = &intel_crtc->config->scaler_state;
@@ -3185,6 +3186,14 @@ static void skl_detach_scalers(struct intel_crtc *intel_crtc)
if (!scaler_state->scalers[i].in_use)
skl_detach_scaler(intel_crtc, i);
}
+
+ if (IS_GEMINILAKE(dev_priv)) {
+ u32 tmp;
+
+ tmp = I915_READ(CLKGATE_DIS_PSL(intel_crtc->pipe));
+ tmp &= ~DPF_GATING_DIS;
+ I915_WRITE(CLKGATE_DIS_PSL(intel_crtc->pipe), tmp);
+ }
}
u32 skl_plane_stride(const struct drm_framebuffer *fb, int plane,
@@ -4763,6 +4772,14 @@ static void skylake_pfit_enable(struct intel_crtc *crtc)
if (WARN_ON(crtc->config->scaler_state.scaler_id < 0))
return;
+ if (IS_GEMINILAKE(dev_priv)) {
+ u32 tmp;
+
+ tmp = I915_READ(CLKGATE_DIS_PSL(crtc->pipe));
+ tmp |= DPF_GATING_DIS;
+ I915_WRITE(CLKGATE_DIS_PSL(crtc->pipe), tmp);
+ }
+
id = scaler_state->scaler_id;
I915_WRITE(SKL_PS_CTRL(pipe, id), PS_SCALER_EN |
PS_FILTER_MEDIUM | scaler_state->scalers[id].mode);
--
2.9.3
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