i915: ensure that VGA plane is disabled

commit 0fde901f1ddd2ce0e380a6444f1fb7ca555859e9 upstream.

Some broken systems (like HP nc6120) in some cases, usually after LID
close/open, enable VGA plane, making display unusable (black screen on LVDS,
some strange mode on VGA output). We used to disable VGA plane only once at
startup. Now we also check, if VGA plane is still disabled while changing
mode, and fix that if something changed it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=57434
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2: intel_modeset_setup_hw_state() does not
 exist, so call i915_redisable_vga() directly from intel_lid_notify()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 232119ac266f3263d323da3dc25d9f93bde6a5b8..774ea5e49660c793b1ff2ee646e157958b29834d 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1397,6 +1397,7 @@ static inline void intel_unregister_dsm_handler(void) { return; }
 #endif /* CONFIG_ACPI */
 
 /* modesetting */
+extern void i915_redisable_vga(struct drm_device *dev);
 extern void intel_modeset_init(struct drm_device *dev);
 extern void intel_modeset_gem_init(struct drm_device *dev);
 extern void intel_modeset_cleanup(struct drm_device *dev);

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5647ce4b3ec7c110c87088f8658ae71a3fcd156a..6b6cf17133ea6324c571b6f77971ab6d8f8373a4 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9254,6 +9254,23 @@ static void i915_disable_vga(struct drm_device *dev)
        POSTING_READ(vga_reg);
 }
 
+void i915_redisable_vga(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 vga_reg;
+
+       if (HAS_PCH_SPLIT(dev))
+               vga_reg = CPU_VGACNTRL;
+       else
+               vga_reg = VGACNTRL;
+
+       if (I915_READ(vga_reg) != VGA_DISP_DISABLE) {
+               DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n");
+               I915_WRITE(vga_reg, VGA_DISP_DISABLE);
+               POSTING_READ(vga_reg);
+       }
+}
+
 void intel_modeset_init(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index dc7c5f6415a7b76ab24fd02d80ea003b014e4454..4f2019b2c166cee70c09f603c915a9d4087148c1 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -535,6 +535,7 @@ static int intel_lid_notify(struct notifier_block *nb, unsigned long val,
 
        mutex_lock(&dev->mode_config.mutex);
        drm_helper_resume_force_mode(dev);
+       i915_redisable_vga(dev);
        mutex_unlock(&dev->mode_config.mutex);
 
        return NOTIFY_OK;