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drm/i915: fix up pch pll handling in ->mode_set

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We ->mode_set is called we can't just blindly reuse an existing pll
since that might be shared with a different, still active pch output.

v2: Only update the pll settings when the pch pll is know to be
unused, otherwise we can wreak havoc with a running pipe. Which in the
case of DP will likely result in a black screen due to loss of link
lock.

v3: Tighten up the asserts a bit more, especially make sure that the
pch pll is still enabled when we try to disable it. This would have
caught the bug fixed in this patch.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter 2013-06-05 13:34:03 +02:00
parent b6f3eff713
commit cdbd2316a0
1 changed files with 19 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpu/drm/i915/intel_display.c
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@ -1427,7 +1427,8 @@ static void ironlake_enable_pch_pll(struct intel_crtc *intel_crtc)
/* PCH refclock must be enabled first */ /* PCH refclock must be enabled first */
assert_pch_refclk_enabled(dev_priv); assert_pch_refclk_enabled(dev_priv);
if (pll->active++ && pll->on) { if (pll->active++) {
WARN_ON(!pll->on);
assert_pch_pll_enabled(dev_priv, pll, NULL); assert_pch_pll_enabled(dev_priv, pll, NULL);
return; return;
} }
@ -1468,10 +1469,9 @@ static void intel_disable_pch_pll(struct intel_crtc *intel_crtc)
return; return;
} }
if (--pll->active) {
assert_pch_pll_enabled(dev_priv, pll, NULL); assert_pch_pll_enabled(dev_priv, pll, NULL);
if (--pll->active)
return; return;
}
DRM_DEBUG_KMS("disabling PCH PLL %x\n", pll->pll_reg); DRM_DEBUG_KMS("disabling PCH PLL %x\n", pll->pll_reg);
@ -3081,9 +3081,9 @@ static struct intel_pch_pll *intel_get_pch_pll(struct intel_crtc *intel_crtc, u3
pll = intel_crtc->pch_pll; pll = intel_crtc->pch_pll;
if (pll) { if (pll) {
DRM_DEBUG_KMS("CRTC:%d reusing existing PCH PLL %x\n", DRM_DEBUG_KMS("CRTC:%d dropping existing PCH PLL %x\n",
intel_crtc->base.base.id, pll->pll_reg); intel_crtc->base.base.id, pll->pll_reg);
goto prepare; intel_put_pch_pll(intel_crtc);
} }
if (HAS_PCH_IBX(dev_priv->dev)) { if (HAS_PCH_IBX(dev_priv->dev)) {
@ -3128,10 +3128,11 @@ static struct intel_pch_pll *intel_get_pch_pll(struct intel_crtc *intel_crtc, u3
found: found:
intel_crtc->pch_pll = pll; intel_crtc->pch_pll = pll;
pll->refcount++;
DRM_DEBUG_DRIVER("using pll %d for pipe %c\n", i, pipe_name(intel_crtc->pipe)); DRM_DEBUG_DRIVER("using pll %d for pipe %c\n", i, pipe_name(intel_crtc->pipe));
prepare: /* separate function? */ if (pll->active == 0) {
DRM_DEBUG_DRIVER("switching PLL %x off\n", pll->pll_reg); DRM_DEBUG_DRIVER("setting up pll %d\n", i);
WARN_ON(pll->on);
assert_pch_pll_disabled(dev_priv, pll, NULL);
/* Wait for the clocks to stabilize before rewriting the regs */ /* Wait for the clocks to stabilize before rewriting the regs */
I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE); I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE);
@ -3140,7 +3141,9 @@ prepare: /* separate function? */
I915_WRITE(pll->fp0_reg, fp); I915_WRITE(pll->fp0_reg, fp);
I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE); I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE);
pll->on = false; }
pll->refcount++;
return pll; return pll;
} }