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.fagerl...@gmail.com> Reported-by: "Li, Weinan Z" <weinan.z...@intel.com> Cc: Chris Wilson <ch...@chris-wilson.co.uk> Cc: sta...@vger.kernel.org Signed-off-by: Lukas Wunner <lu...@wunner.de> --- drivers/gpu/drm/i915/i915_dma.c | 8 +++----- drivers/gpu/drm/i915/intel_fbdev.c | 3 +++ 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 4aa3db6..9d76dfb 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -430,11 +430,9 @@ static int i915_load_modeset_init(struct drm_device *dev) * Some ports require correctly set-up hpd registers for detection to * work properly (leading to ghost connected connector status), e.g. VGA * on gm45. Hence we can only set up the initial fbdev config after hpd - * irqs are fully enabled. Now we should scan for the initial config - * only once hotplug handling is enabled, but due to screwed-up locking - * around kms/fbdev init we can't protect the fdbev initial config - * scanning against hotplug events. Hence do this first and ignore the - * tiny window where we will loose hotplug notifactions. + * irqs are fully enabled. We protect the fbdev initial config scanning + * against hotplug events by waiting in intel_fbdev_output_poll_changed + * until the asynchronous thread has finished. */ intel_fbdev_initial_config_async(dev); diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c index ae9cf6f..7e73acc 100644 --- a/drivers/gpu/drm/i915/intel_fbdev.c +++ b/drivers/gpu/drm/i915/intel_fbdev.c @@ -800,6 +800,8 @@ 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); } @@ -811,6 +813,7 @@ 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; -- 1.8.5.2 (Apple Git-48) _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
