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| author | Lukas Wunner <lukas@wunner.de> | 2016-03-09 12:52:53 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-03-30 08:23:41 +0200 |
| commit | a7442b93cf32c1e1ddb721a26cd1f92302e2a222 (patch) | |
| tree | ed0e8f9b8cf0a4b151dacbf94c1e9f608e8ca3f5 /drivers/gpu/drm/i915/i915_dma.c | |
| parent | 583349896482ed1d6af3cd75b2a15bb334df2777 (diff) | |
| download | linux-a7442b93cf32c1e1ddb721a26cd1f92302e2a222.tar.bz2 | |
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/i915_dma.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_dma.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index fc8ac98c12d7..1ac1ea969eec 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -493,11 +493,9 @@ 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); |