From nobody Sun Feb 8 02:26:11 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EE4FC77B73 for ; Thu, 1 Jun 2023 00:49:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229996AbjFAAtG (ORCPT ); Wed, 31 May 2023 20:49:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229476AbjFAAtE (ORCPT ); Wed, 31 May 2023 20:49:04 -0400 Received: from mail.aspeedtech.com (mail.aspeedtech.com [211.20.114.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 015FA119 for ; Wed, 31 May 2023 17:48:55 -0700 (PDT) Received: from JammyHuang-PC.aspeed.com (192.168.2.115) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 1 Jun 2023 08:48:51 +0800 From: Jammy Huang To: , , , CC: , Subject: [PATCH v3] drm/ast: Fix modeset failed on DisplayPort Date: Thu, 1 Jun 2023 08:48:47 +0800 Message-ID: <20230601004847.1115-1-jammy_huang@aspeedtech.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [192.168.2.115] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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: Thomas Zimmermann Signed-off-by: Jammy Huang --- v3 changes: - Update label name after mutex added. v2 changes: - Fix build error since new struct ast_device is used. --- drivers/gpu/drm/ast/ast_mode.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index 36374828f6c8..b3c670af6ef2 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -1647,6 +1647,8 @@ static int ast_dp501_output_init(struct ast_device *a= st) static int ast_astdp_connector_helper_get_modes(struct drm_connector *conn= ector) { void *edid; + struct drm_device *dev =3D connector->dev; + struct ast_device *ast =3D to_ast_device(dev); =20 int succ; int count; @@ -1655,9 +1657,17 @@ static int ast_astdp_connector_helper_get_modes(stru= ct drm_connector *connector) if (!edid) goto err_drm_connector_update_edid_property; =20 + /* + * Protect access to I/O registers from concurrent modesetting + * by acquiring the I/O-register lock. + */ + mutex_lock(&ast->ioregs_lock); + succ =3D ast_astdp_read_edid(connector->dev, edid); if (succ < 0) - goto err_kfree; + goto err_mutex_unlock; + + mutex_unlock(&ast->ioregs_lock); =20 drm_connector_update_edid_property(connector, edid); count =3D drm_add_edid_modes(connector, edid); @@ -1665,7 +1675,8 @@ static int ast_astdp_connector_helper_get_modes(struc= t drm_connector *connector) =20 return count; =20 -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); base-commit: e338142b39cf40155054f95daa28d210d2ee1b2d --=20 2.25.1