On Wed, Mar 09, 2016 at 12:52:53PM +0100, Lukas Wunner wrote: > 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@xxxxxxxxx> > Reported-by: "Li, Weinan Z" <weinan.z.li@xxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> Queued for -next, thanks for the patch. -Daniel > --- > 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@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
