From: Daniel Vetter Date: Wed, 5 Jun 2013 11:34:32 +0000 (+0200) Subject: drm/i915: Fix up cpt pixel multiplier enable sequence X-Git-Tag: firefly_0821_release~176^2~5263^2~179^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3ad8a208abbe1bdfe31512053a81ac4938aed447;p=firefly-linux-kernel-4.4.55.git drm/i915: Fix up cpt pixel multiplier enable sequence Bspec for the "DPLL HDMI multiplier" field says: "Restriction : The DPLL must be enabled and stable before setting these bits. These bits must be programmed after DPLL_SEL is programmed." There is apparently no restriction on programming the DPLL_SEL register wrt the DPLL. So let's just move that up before we enable the pch dpll. Reviewed-by: Imre Deak Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index abaae78f0c52..3d1c97abee28 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3004,15 +3004,8 @@ static void ironlake_pch_enable(struct drm_crtc *crtc) /* For PCH output, training FDI link */ dev_priv->display.fdi_link_train(crtc); - /* XXX: pch pll's can be enabled any time before we enable the PCH - * transcoder, and we actually should do this to not upset any PCH - * transcoder that already use the clock when we share it. - * - * Note that enable_shared_dpll tries to do the right thing, but - * get_shared_dpll unconditionally resets the pll - we need that to have - * the right LVDS enable sequence. */ - ironlake_enable_shared_dpll(intel_crtc); - + /* We need to program the right clock selection before writing the pixel + * mutliplier into the DPLL. */ if (HAS_PCH_CPT(dev)) { u32 sel; @@ -3026,6 +3019,15 @@ static void ironlake_pch_enable(struct drm_crtc *crtc) I915_WRITE(PCH_DPLL_SEL, temp); } + /* XXX: pch pll's can be enabled any time before we enable the PCH + * transcoder, and we actually should do this to not upset any PCH + * transcoder that already use the clock when we share it. + * + * Note that enable_shared_dpll tries to do the right thing, but + * get_shared_dpll unconditionally resets the pll - we need that to have + * the right LVDS enable sequence. */ + ironlake_enable_shared_dpll(intel_crtc); + /* set transcoder timing, panel must allow it */ assert_panel_unlocked(dev_priv, pipe); ironlake_pch_transcoder_set_timings(intel_crtc, pipe);