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d1b894c5bb
A probe-time deadlock can occur between the dequeue worker and
drm_client_register(). During probe, drm_client_register() holds
clientlist_mutex and calls the fbdev hotplug callback, which triggers an
atomic commit that ends up sleeping in virtio_gpu_queue_ctrl_sgs()
waiting for virtqueue space. The dequeue worker that would free that
space calls virtio_gpu_cmd_get_display_info_cb(), which invokes
drm_kms_helper_hotplug_event() -> drm_client_dev_hotplug(), attempting
to acquire the same clientlist_mutex. Since wake_up() is only called
after the resp_cb loop, the probe thread is never woken and both threads
deadlock.
Fix this by removing the hotplug notification from
virtio_gpu_cmd_get_display_info_cb(). The display data (outputs[i].info)
is still updated synchronously in the callback.
For the init path, drm_client_register() already fires an initial
hotplug when the client is registered, which picks up the connector
state updated by display_info_cb.
For the runtime config_changed path, add a wait_event_timeout() in
config_changed_work_func() so that display_info_cb updates the connector
data before the hotplug notification is sent. Also replace
drm_helper_hpd_irq_event() with drm_kms_helper_hotplug_event() since
virtio-gpu never calls drm_kms_helper_poll_init() and thus
drm_helper_hpd_irq_event() always returns false without doing anything.
Fixes:
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| virtgpu_debugfs.c | ||
| virtgpu_display.c | ||
| virtgpu_drv.c | ||
| virtgpu_drv.h | ||
| virtgpu_fence.c | ||
| virtgpu_gem.c | ||
| virtgpu_ioctl.c | ||
| virtgpu_kms.c | ||
| virtgpu_object.c | ||
| virtgpu_plane.c | ||
| virtgpu_prime.c | ||
| virtgpu_submit.c | ||
| virtgpu_trace_points.c | ||
| virtgpu_trace.h | ||
| virtgpu_vq.c | ||
| virtgpu_vram.c | ||