Commit 3692abab authored by Jammy Huang's avatar Jammy Huang Committed by Thomas Zimmermann
Browse files

drm/ast: Fix modeset failed on DisplayPort 



If we switch display and update cursor together, it could lead to
modeset failed because of concurrent access to IO registers.

Add lock protection in DP's edid access to avoid this problem.

Reviewed-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarJammy Huang <jammy_huang@aspeedtech.com>
Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230601004847.1115-1-jammy_huang@aspeedtech.com
parent bed61c8f

drivers/gpu/drm/ast/ast_mode.c

+13 −2
Original line number Diff line number Diff line
@@ -1647,6 +1647,8 @@ static int ast_dp501_output_init(struct ast_device *ast) 
static int ast_astdp_connector_helper_get_modes(struct drm_connector *connector)

{

	void *edid;

	struct drm_device *dev = connector->dev;

	struct ast_device *ast = to_ast_device(dev);



	int succ;

	int count;
@@ -1655,9 +1657,17 @@ static int ast_astdp_connector_helper_get_modes(struct drm_connector *connector) 
	if (!edid)

		goto err_drm_connector_update_edid_property;



	/*

	 * Protect access to I/O registers from concurrent modesetting

	 * by acquiring the I/O-register lock.

	 */

	mutex_lock(&ast->ioregs_lock);



	succ = ast_astdp_read_edid(connector->dev, edid);

	if (succ < 0)

		goto err_kfree;

		goto err_mutex_unlock;



	mutex_unlock(&ast->ioregs_lock);



	drm_connector_update_edid_property(connector, edid);

	count = drm_add_edid_modes(connector, edid);
@@ -1665,7 +1675,8 @@ static int ast_astdp_connector_helper_get_modes(struct drm_connector *connector) 


	return count;



err_kfree:

err_mutex_unlock:

	mutex_unlock(&ast->ioregs_lock);

	kfree(edid);

err_drm_connector_update_edid_property:

	drm_connector_update_edid_property(connector, NULL);