From 8dc8a27c9733a41cda84e8c70da8313e1d54c4ae Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Fri, 2 Aug 2013 16:22:24 -0300 Subject: [PATCH] drm/i915: check the power well when redisabling VGA If the power well is disabled VGA is guaranteed to be disabled. This fixes unclaimed register messages that happen on suspend/resume. v2: Check the actual hw power well state instead of our own tracking to make sure VGA is _really_ off (in case the BIOS/KVMr has just its own request bit set). Requested by Ville. Note: Ville suggested whether it wouldn't be better to just enable the power well over a slightly longer time in our resume code, since we already do that. I tend to agree, but there's also the modeset force code in the lid notifier which _also_ eventually calls redisable_vga. We shouldn't ever need this on somewhat modern hw (everything with opregion essentially) but the code to bail out isn't there. Hence stick with this simple approach here for now. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67517 Signed-off-by: Paulo Zanoni [danvet: Summarize the discussion around the resume sequence and lid notifier a bit.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index a87bb93a0f63..f83316ec0b94 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -10104,6 +10104,17 @@ void i915_redisable_vga(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; u32 vga_reg = i915_vgacntrl_reg(dev); + /* This function can be called both from intel_modeset_setup_hw_state or + * at a very early point in our resume sequence, where the power well + * structures are not yet restored. Since this function is at a very + * paranoid "someone might have enabled VGA while we were not looking" + * level, just check if the power well is enabled instead of trying to + * follow the "don't touch the power well if we don't need it" policy + * the rest of the driver uses. */ + if (HAS_POWER_WELL(dev) && + (I915_READ(HSW_PWR_WELL_DRIVER) & HSW_PWR_WELL_STATE) == 0) + return; + if (I915_READ(vga_reg) != VGA_DISP_DISABLE) { DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n"); i915_disable_vga(dev); -- GitLab