From 23a7068ec581fcc6fb61039448632d25987b1fae Mon Sep 17 00:00:00 2001 From: James Ausmus Date: Thu, 30 Nov 2017 18:17:00 -0800 Subject: [PATCH] drm/i915/cnl: Mask previous DDI - PLL mapping Without masking out the old value, we can end up pointing the DDI to a disabled PLL, which makes the system fall over. Mask out the previous value before setting the PLL to DDI mapping. This can be observed by running igt/testdisplay with both an eDP and HDMI/DP output active. v2: Add the Bugzilla link Fixes: 555e38d273172 ("drm/i915/cnl: DDI - PLL mapping") Testcase: igt/testdisplay Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103997 Cc: Rodrigo Vivi Cc: Matt Atwood Signed-off-by: James Ausmus Reviewed-by: Rodrigo Vivi Tested-by: Rodrigo Vivi Signed-off-by: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/20171201021700.13504-1-james.ausmus@intel.com --- drivers/gpu/drm/i915/intel_ddi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 48ba9b7fdc78..369f780588fb 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -2098,6 +2098,7 @@ static void intel_ddi_clk_select(struct intel_encoder *encoder, if (IS_CANNONLAKE(dev_priv)) { /* Configure DPCLKA_CFGCR0 to map the DPLL to the DDI. */ val = I915_READ(DPCLKA_CFGCR0); + val &= ~DPCLKA_CFGCR0_DDI_CLK_SEL_MASK(port); val |= DPCLKA_CFGCR0_DDI_CLK_SEL(pll->id, port); I915_WRITE(DPCLKA_CFGCR0, val); -- GitLab