From bfa3384a9a84aaaa59443bbd776c142e7dba4b0f Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Tue, 10 Apr 2012 11:58:04 -0700 Subject: [PATCH] drm/i915: check PPS regs for sanity when using eDP If these regs don't have valid values, the panel won't come up, and may even cause a system hang. So do a basic sanity check when an eDP panel is detected. Signed-off-by: Jesse Barnes Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44305 Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 110552ff302c..6346b29ee934 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -2462,6 +2462,13 @@ intel_dp_init(struct drm_device *dev, int output_reg) pp_off = I915_READ(PCH_PP_OFF_DELAYS); pp_div = I915_READ(PCH_PP_DIVISOR); + if (!pp_on || !pp_off || !pp_div) { + DRM_INFO("bad panel power sequencing delays, disabling panel\n"); + intel_dp_encoder_destroy(&intel_dp->base.base); + intel_dp_destroy(&intel_connector->base); + return; + } + /* Pull timing values out of registers */ cur.t1_t3 = (pp_on & PANEL_POWER_UP_DELAY_MASK) >> PANEL_POWER_UP_DELAY_SHIFT;