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Commit 7147573a authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/gma500: move fbcon restore to lastclose 



Doing this within the fb->destroy callback leads to a locking
nightmare. And all other drm drivers that restore the fbcon do
it in lastclose, too.

With this adjustments all fb->destroy callbacks optionally drop
references to any gem objects used as backing storage, call
drm_framebuffer_cleanup and then kfree the struct. Which nicely
simplifies the locking for framebuffer unreferencing and freeing,
since this doesn't require that we hold the mode_config lock. A
slight exception is the vmwgfx surface backed framebuffer, it also
calls drm_master_put and removes the object from a device-private
framebuffer list. Both seem to have solid locking in place already.

Conclusion is that now it is no longer required to hold the
mode_config lock while freeing a framebuffer.

v2: Drop the corresponding mutex_lock WARN check from
drm_framebuffer_unreference.

v3: Use just the mode_config lock not modeset_lock_all, due to patch
reordering.

Acked-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 80f0b5af

drivers/gpu/drm/drm_crtc.c

+0 −2
Original line number Diff line number Diff line
@@ -317,9 +317,7 @@ static void drm_framebuffer_free(struct kref *kref) 
 */

void drm_framebuffer_unreference(struct drm_framebuffer *fb)

{

	struct drm_device *dev = fb->dev;

	DRM_DEBUG("FB ID: %d\n", fb->base.id);

	WARN_ON(!drm_modeset_is_locked(dev));

	kref_put(&fb->refcount, drm_framebuffer_free);

}

EXPORT_SYMBOL(drm_framebuffer_unreference);

drivers/gpu/drm/gma500/framebuffer.c

+0 −24
Original line number Diff line number Diff line
@@ -668,30 +668,6 @@ static void psb_user_framebuffer_destroy(struct drm_framebuffer *fb) 
{

	struct psb_framebuffer *psbfb = to_psb_fb(fb);

	struct gtt_range *r = psbfb->gtt;

	struct drm_device *dev = fb->dev;

	struct drm_psb_private *dev_priv = dev->dev_private;

	struct psb_fbdev *fbdev = dev_priv->fbdev;

	struct drm_crtc *crtc;

	int reset = 0;



	/* Should never get stolen memory for a user fb */

	WARN_ON(r->stolen);



	/* Check if we are erroneously live */

	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)

		if (crtc->fb == fb)

			reset = 1;



	if (reset)

		/*

		 * Now force a sane response before we permit the DRM CRTC

		 * layer to do stupid things like blank the display. Instead

		 * we reset this framebuffer as if the user had forced a reset.

		 * We must do this before the cleanup so that the DRM layer

		 * doesn't get a chance to stick its oar in where it isn't

		 * wanted.

		 */

		drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper);



	/* Let DRM do its clean up */

	drm_framebuffer_cleanup(fb);

drivers/gpu/drm/gma500/psb_drv.c

+10 −0
Original line number Diff line number Diff line
@@ -149,6 +149,16 @@ static struct drm_ioctl_desc psb_ioctls[] = { 


static void psb_lastclose(struct drm_device *dev)

{

	int ret;

	struct drm_psb_private *dev_priv = dev->dev_private;

	struct psb_fbdev *fbdev = dev_priv->fbdev;



	mutex_lock(&dev->mode_config.mutex);

	ret = drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper);

	if (ret)

		DRM_DEBUG("failed to restore crtc mode\n");

	mutex_unlock(&dev->mode_config.mutex);



	return;

}