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authorLukas Wunner <lukas@wunner.de>2016-03-09 12:52:53 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-03-30 08:23:41 +0200
commita7442b93cf32c1e1ddb721a26cd1f92302e2a222 (patch)
treeed0e8f9b8cf0a4b151dacbf94c1e9f608e8ca3f5 /drivers/gpu/drm/i915/intel_fbdev.c
parent583349896482ed1d6af3cd75b2a15bb334df2777 (diff)
downloadop-kernel-dev-a7442b93cf32c1e1ddb721a26cd1f92302e2a222.zip
op-kernel-dev-a7442b93cf32c1e1ddb721a26cd1f92302e2a222.tar.gz
drm/i915: Fix races on fbdev
The ->lastclose callback invokes intel_fbdev_restore_mode() and has been witnessed to run before intel_fbdev_initial_config_async() has finished. We might likewise receive hotplug events before we've had a chance to fully set up the fbdev. Fix by waiting for the asynchronous thread to finish. v2: An async_synchronize_full() was also added to intel_fbdev_set_suspend() in v1 which turned out to be entirely gratuitous. It caused a deadlock on suspend (discovered by CI, thanks to Damien Lespiau and Tomi Sarvela for CI support) and was unnecessary since a device is never suspended until its ->probe callback (and all asynchronous tasks it scheduled) have finished. See dpm_prepare(), which calls wait_for_device_probe(), which calls async_synchronize_full(). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93580 Reported-by: Gustav Fägerlind <gustav.fagerlind@gmail.com> Reported-by: "Li, Weinan Z" <weinan.z.li@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: stable@vger.kernel.org Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20160309115147.67B2B6E0D3@gabe.freedesktop.org
Diffstat (limited to 'drivers/gpu/drm/i915/intel_fbdev.c')
-rw-r--r--drivers/gpu/drm/i915/intel_fbdev.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 5e0dcb3..153ea7a3 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -808,6 +808,8 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous
void intel_fbdev_output_poll_changed(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
+
+ async_synchronize_full();
if (dev_priv->fbdev)
drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
}
@@ -819,6 +821,7 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
struct intel_fbdev *ifbdev = dev_priv->fbdev;
struct drm_fb_helper *fb_helper;
+ async_synchronize_full();
if (!ifbdev)
return;
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