From f00b56896ec2443a33277f5411de0cbd13071cec Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Tue, 15 Mar 2016 16:40:03 +0200 Subject: drm/i915: Power down the DSI PLL before reconfiguring it MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On VLV at least, the BIOS may leave the DSI PLL enabled in some wonky state where it just refuses to lock. Simply disabling the PLL before reconfiguring it is not enough to fix it, but power gating the PLL prior to reconfiguring does work. This happens on BYT FFRD8 when booting with HDMI connected so the DSI display will not be lit up by the BIOS. Also we can remove the code for BXT that disables the PLL before enabling it again. v2: s/vlv/intel/ since BXT made thing generic v3: Remove the BXT disable PLL before enable trick Signed-off-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1458052809-23426-11-git-send-email-ville.syrjala@linux.intel.com Acked-by: Jani Nikula --- drivers/gpu/drm/i915/intel_dsi.c | 6 ++++++ drivers/gpu/drm/i915/intel_dsi_pll.c | 8 -------- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c index a1e0547484ae..9ff6435e7d38 100644 --- a/drivers/gpu/drm/i915/intel_dsi.c +++ b/drivers/gpu/drm/i915/intel_dsi.c @@ -505,7 +505,13 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder) DRM_DEBUG_KMS("\n"); + /* + * The BIOS may leave the PLL in a wonky state where it doesn't + * lock. It needs to be fully powered down to fix it. + */ + intel_disable_dsi_pll(encoder); intel_enable_dsi_pll(encoder); + intel_dsi_prepare(encoder); /* Panel Enable over CRC PMIC */ diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index 6d497daefdb0..bd17465018f4 100644 --- a/drivers/gpu/drm/i915/intel_dsi_pll.c +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c @@ -484,14 +484,6 @@ static void bxt_enable_dsi_pll(struct intel_encoder *encoder) DRM_DEBUG_KMS("\n"); - val = I915_READ(BXT_DSI_PLL_ENABLE); - - if (val & BXT_DSI_PLL_DO_ENABLE) { - WARN(1, "DSI PLL already enabled. Disabling it.\n"); - val &= ~BXT_DSI_PLL_DO_ENABLE; - I915_WRITE(BXT_DSI_PLL_ENABLE, val); - } - /* Configure PLL vales */ if (!bxt_configure_dsi_pll(encoder)) { DRM_ERROR("Configure DSI PLL failed, abort PLL enable\n"); -- cgit v1.2.3