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drm/i915: vlv: W/a for hotplug/manual VGA detection

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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.chan@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.lahtinen@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Imre Deak 2014-01-09 17:08:16 +02:00 committed by Daniel Vetter
parent 404faabc3f
commit e5cbfbfb2e
1 changed files with 15 additions and 4 deletions
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19
drivers/gpu/drm/i915/intel_display.c
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@ -1374,8 +1374,12 @@ 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);
/*
@ -1504,9 +1508,12 @@ 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));
}
@ -4983,7 +4990,11 @@ 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 */