VGA detection requires the reference clock to be on, so make sure this
is the case.
This fixes VGA hotplug/manual detection where all pipes are off and so
we would normally disable all clocks.
v2:
- Instead of disabling PSR clock gating, force the reference clock on
through the DPLL_A register. (Kin Chan S <kin.s.c...@intel.com>)
v3:
- Move enabling of the clock to intel_reset_dpio() and use the DPLL_B
register instead, where we already have a similar tweak for the CRI
clock. (Ville)
Reported-by: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Signed-off-by: Imre Deak <imre.d...@intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index 3262ac4..4e2598b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1377,8 +1377,12 @@ static void intel_reset_dpio(struct drm_device *dev)
if (!IS_VALLEYVIEW(dev))
return;
- /* Enable the CRI clock source so we can get at the display */
+ /*
+ * Enable the CRI clock source so we can get at the display and the
+ * reference clock for VGA hotplug / manual detection.
+ */
I915_WRITE(DPLL(PIPE_B), I915_READ(DPLL(PIPE_B)) |
+ DPLL_REFA_CLK_ENABLE_VLV |
DPLL_INTEGRATED_CRI_CLK_VLV);
/*
@@ -1507,9 +1511,12 @@ static void vlv_disable_pll(struct drm_i915_private
*dev_priv, enum pipe pipe)
/* Make sure the pipe isn't still relying on us */
assert_pipe_disabled(dev_priv, pipe);
- /* Leave integrated clock source enabled */
+ /*
+ * Leave integrated clock source and reference clock enabled for pipe B.
+ * The latter is needed for VGA hotplug / manual detection.
+ */
if (pipe == PIPE_B)
- val = DPLL_INTEGRATED_CRI_CLK_VLV;
+ val = DPLL_INTEGRATED_CRI_CLK_VLV | DPLL_REFA_CLK_ENABLE_VLV;
I915_WRITE(DPLL(pipe), val);
POSTING_READ(DPLL(pipe));
}
@@ -4986,7 +4993,11 @@ static void vlv_update_pll(struct intel_crtc *crtc)
vlv_dpio_write(dev_priv, pipe, VLV_PLL_DW11(pipe), 0x87871000);
- /* Enable DPIO clock input */
+ /*
+ * Enable DPIO clock input. We should never disable the reference
+ * clock for pipe B, since VGA hotplug / manual detection depends
+ * on it.
+ */
dpll = DPLL_EXT_BUFFER_ENABLE_VLV | DPLL_REFA_CLK_ENABLE_VLV |
DPLL_VGA_MODE_DIS | DPLL_INTEGRATED_CLOCK_VLV;
/* We should never disable this, set it here for state tracking */
--
1.8.4
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