Cc: Ben Widawsky <ben at bwidawsk.net>
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
---
drivers/gpu/drm/i915/intel_display.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d5aa2d2..b97112c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2845,11 +2845,14 @@ found:
DRM_DEBUG_DRIVER("using pll %d for pipe %d\n", i, intel_crtc->pipe);
prepare: /* separate function? */
DRM_DEBUG_DRIVER("switching PLL %x off\n", pll->pll_reg);
- I915_WRITE(pll->fp0_reg, fp);
- I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE);
+ /* Wait for the clocks to stabilize before rewriting the regs */
+ I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE);
POSTING_READ(pll->pll_reg);
udelay(150);
+
+ I915_WRITE(pll->fp0_reg, fp);
+ I915_WRITE(pll->pll_reg, dpll & ~DPLL_VCO_ENABLE);
pll->on = false;
return pll;
}
--
1.7.10
