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Commit 21fbd085 authored by Thomas Hellstrom's avatar Thomas Hellstrom
Browse files

drm/vmwgfx: Clean up fbdev modeset locking 



At least since the atomic port, the vmwgfx fbdev code is taking
a number of unnecessary modeset locks. In particular the
kms_set_config() function will grab its own locks, leading to
locking retries. So avoid drm_modeset_lock_all() and instead
provide a local acquire context for kms_set_config(). Also have the
vmw_kms_fbdev_init data itself grab the lock that it needs.

This also fixed a long standing problem that vmw_fb_close() didn't
provide an acquire context for kms_set_config(), causing potential
warnings and hangs during driver unload. This problem was uncovered by the
recent commit "drm/vmwgfx: Improve on hibernation"

Testing done:
Repeated driver load and unload on Ubuntu 16.04.2

Fixes: c3b9b165 ("drm/vmwgfx: Improve on hibernation")
Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarDeepak Rawat <drawat@vmware.com>
Reviewed-by: default avatarSinclair Yeh <syeh@vmware.com>
parent bb1278e8

drivers/gpu/drm/vmwgfx/vmwgfx_fb.c

+10 −21
Original line number Diff line number Diff line
@@ -441,11 +441,11 @@ static int vmwgfx_set_config_internal(struct drm_mode_set *set) 
	struct drm_crtc *crtc = set->crtc;

	struct drm_framebuffer *fb;

	struct drm_crtc *tmp;

	struct drm_modeset_acquire_ctx *ctx;

	struct drm_device *dev = set->crtc->dev;

	struct drm_modeset_acquire_ctx ctx;

	int ret;



	ctx = dev->mode_config.acquire_ctx;

	drm_modeset_acquire_init(&ctx, 0);



restart:

	/*
@@ -458,7 +458,7 @@ static int vmwgfx_set_config_internal(struct drm_mode_set *set) 


	fb = set->fb;



	ret = crtc->funcs->set_config(set, ctx);

	ret = crtc->funcs->set_config(set, &ctx);

	if (ret == 0) {

		crtc->primary->crtc = crtc;

		crtc->primary->fb = fb;
@@ -473,20 +473,13 @@ static int vmwgfx_set_config_internal(struct drm_mode_set *set) 
	}



	if (ret == -EDEADLK) {

		dev->mode_config.acquire_ctx = NULL;



retry_locking:

		drm_modeset_backoff(ctx);



		ret = drm_modeset_lock_all_ctx(dev, ctx);

		if (ret)

			goto retry_locking;



		dev->mode_config.acquire_ctx = ctx;



		drm_modeset_backoff(&ctx);

		goto restart;

	}



	drm_modeset_drop_locks(&ctx);

	drm_modeset_acquire_fini(&ctx);



	return ret;

}
@@ -624,7 +617,6 @@ static int vmw_fb_set_par(struct fb_info *info) 
	}



	mutex_lock(&par->bo_mutex);

	drm_modeset_lock_all(vmw_priv->dev);

	ret = vmw_fb_kms_framebuffer(info);

	if (ret)

		goto out_unlock;
@@ -657,7 +649,6 @@ static int vmw_fb_set_par(struct fb_info *info) 
		drm_mode_destroy(vmw_priv->dev, old_mode);

	par->set_mode = mode;



	drm_modeset_unlock_all(vmw_priv->dev);

	mutex_unlock(&par->bo_mutex);



	return ret;
@@ -713,18 +704,14 @@ int vmw_fb_init(struct vmw_private *vmw_priv) 
	par->max_width = fb_width;

	par->max_height = fb_height;



	drm_modeset_lock_all(vmw_priv->dev);

	ret = vmw_kms_fbdev_init_data(vmw_priv, 0, par->max_width,

				      par->max_height, &par->con,

				      &par->crtc, &init_mode);

	if (ret) {

		drm_modeset_unlock_all(vmw_priv->dev);

	if (ret)

		goto err_kms;

	}



	info->var.xres = init_mode->hdisplay;

	info->var.yres = init_mode->vdisplay;

	drm_modeset_unlock_all(vmw_priv->dev);



	/*

	 * Create buffers and alloc memory
@@ -832,7 +819,9 @@ int vmw_fb_close(struct vmw_private *vmw_priv) 
	cancel_delayed_work_sync(&par->local_work);

	unregister_framebuffer(info);



	mutex_lock(&par->bo_mutex);

	(void) vmw_fb_kms_detach(par, true, true);

	mutex_unlock(&par->bo_mutex);



	vfree(par->vmalloc);

	framebuffer_release(info);

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

+10 −3
Original line number Diff line number Diff line
@@ -2680,7 +2680,9 @@ int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv, 
	struct vmw_display_unit *du;

	struct drm_display_mode *mode;

	int i = 0;

	int ret = 0;



	mutex_lock(&dev_priv->dev->mode_config.mutex);

	list_for_each_entry(con, &dev_priv->dev->mode_config.connector_list,

			    head) {

		if (i == unit)
@@ -2691,7 +2693,8 @@ int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv, 


	if (i != unit) {

		DRM_ERROR("Could not find initial display unit.\n");

		return -EINVAL;

		ret = -EINVAL;

		goto out_unlock;

	}



	if (list_empty(&con->modes))
@@ -2699,7 +2702,8 @@ int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv, 


	if (list_empty(&con->modes)) {

		DRM_ERROR("Could not find initial display mode.\n");

		return -EINVAL;

		ret = -EINVAL;

		goto out_unlock;

	}



	du = vmw_connector_to_du(con);
@@ -2720,7 +2724,10 @@ int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv, 
					   head);

	}



	return 0;

 out_unlock:

	mutex_unlock(&dev_priv->dev->mode_config.mutex);



	return ret;

}



/**