drm/i915/glk: Validate only DSI PORT A PLL divider
As per BSPEC, GLK supports MIPI DSI 8X clk only on PORT A. Therefore only for PORT A PLL divider value should be validated. Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1487335415-14766-8-git-send-email-madhav.chauhan@intel.com
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@ -206,17 +206,24 @@ static bool bxt_dsi_pll_is_enabled(struct drm_i915_private *dev_priv)
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return false;
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/*
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* Both dividers must be programmed with valid values even if only one
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* of the PLL is used, see BSpec/Broxton Clocks. Check this here for
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* Dividers must be programmed with valid values. As per BSEPC, for
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* GEMINLAKE only PORT A divider values are checked while for BXT
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* both divider values are validated. Check this here for
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* paranoia, since BIOS is known to misconfigure PLLs in this way at
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* times, and since accessing DSI registers with invalid dividers
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* causes a system hang.
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*/
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val = I915_READ(BXT_DSI_PLL_CTL);
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if (!(val & BXT_DSIA_16X_MASK) || !(val & BXT_DSIC_16X_MASK)) {
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DRM_DEBUG_DRIVER("PLL is enabled with invalid divider settings (%08x)\n",
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val);
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enabled = false;
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if (IS_GEMINILAKE(dev_priv)) {
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if (!(val & BXT_DSIA_16X_MASK)) {
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DRM_DEBUG_DRIVER("Invalid PLL divider (%08x)\n", val);
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enabled = false;
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}
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} else {
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if (!(val & BXT_DSIA_16X_MASK) || !(val & BXT_DSIC_16X_MASK)) {
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DRM_DEBUG_DRIVER("Invalid PLL divider (%08x)\n", val);
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enabled = false;
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}
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}
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return enabled;
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