[Intel-gfx] [PATCH] drm/i915/display: Suspend MST topology manager before destroy fbdev

[Lucas De Marchi]

On Tue, Nov 26, 2019 at 06:16:09PM -0800, Jose Souza wrote:
>MST do topology probe in threads, so this running threads needs to be
>flushed before fbdev is destroyed as when a new MST node is found it
>calls drm_kms_helper_hotplug_event() that calls fbdev functions
>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109964
>Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
>---
> drivers/gpu/drm/i915/display/intel_display.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>index 8f2770951459..372dd48691cf 100644
>--- a/drivers/gpu/drm/i915/display/intel_display.c
>+++ b/drivers/gpu/drm/i915/display/intel_display.c
>@@ -17989,6 +17989,13 @@ void intel_modeset_driver_remove(struct drm_i915_private *i915)
> 	 */
> 	intel_hpd_poll_fini(i915);
>
>+	/*
>+	 * MST do topology probe in threads, so this running threads needs to
>+	 * be flushed before fbdev is destroyed as when a new MST node is found
>+	 * it call drm_kms_helper_hotplug_event() that calls fbdev functions
>+	 */

this would normally be part of drm_mode_config_cleanup() in which the
encoders will be destroyed, together with their mst_mgr via 
drm_dp_mst_topology_mgr_destroy()

So I think the comment should actually mention why
drm_mode_config_cleanup() can't be done before or just state where it
will actually be destroyed. So... I guess something like:

/*
  * MST topology needs to be suspended so we don't have any calls to
  * fbdev after it's finalized. MST will be destroyed later as part of
  * drm_mode_config_cleanup()
  */

Of course, if we can figure out a better ordering to peel the onion
would be better, but I think this is sufficient.

With the comment update,


Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>

Lucas De Marchi

>+	intel_dp_mst_suspend(i915);
>+
> 	/* poll work can call into fbdev, hence clean that up afterwards */
> 	intel_fbdev_fini(i915);
>
>-- 
>2.24.0
>
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