From mboxrd@z Thu Jan 1 00:00:00 1970 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D8C4E10F996A for ; Wed, 8 Apr 2026 18:45:13 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2D52C10E075; Wed, 8 Apr 2026 18:45:13 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mHpfvIxI"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id BC12610E075 for ; Wed, 8 Apr 2026 18:45:11 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D7B866011F; Wed, 8 Apr 2026 18:45:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3772EC19421; Wed, 8 Apr 2026 18:45:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775673910; bh=L0nwMJlFWT6JGNIOIUolDR2HdTPIl5o80NM6Ht4lR5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mHpfvIxIJbhyyps7P7HEXG/Ywi2he6JJ6cwoVTf8M4fPysHXK+vskmLgEiPzUzUQS ps55mgaOli+MZ10xgtc5K/RyEwWXdXeVz183FcMqRsfI9Z2muyQP4k/QJ3dK/JcZbs lY0stT9GA+5O3s0ohn/sesgYEhUxLfQE/LHX/jfk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thomas Zimmermann , Jocelyn Falempe , Dave Airlie , dri-devel@lists.freedesktop.org Subject: [PATCH 6.12 135/242] drm/ast: dp501: Fix initialization of SCU2C Date: Wed, 8 Apr 2026 20:02:55 +0200 Message-ID: <20260408175932.141035269@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175927.064985309@linuxfoundation.org> References: <20260408175927.064985309@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Zimmermann commit 2f42c1a6161646cbd29b443459fd635d29eda634 upstream. Ast's DP501 initialization reads the register SCU2C at offset 0x1202c and tries to set it to source data from VGA. But writes the update to offset 0x0, with unknown results. Write the result to SCU instead. The bug only happens in ast_init_analog(). There's similar code in ast_init_dvo(), which works correctly. Signed-off-by: Thomas Zimmermann Fixes: 83c6620bae3f ("drm/ast: initial DP501 support (v0.2)") Reviewed-by: Jocelyn Falempe Cc: Dave Airlie Cc: Thomas Zimmermann Cc: Jocelyn Falempe Cc: dri-devel@lists.freedesktop.org Cc: # v3.16+ Link: https://patch.msgid.link/20260327133532.79696-2-tzimmermann@suse.de Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/ast/ast_dp501.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/gpu/drm/ast/ast_dp501.c +++ b/drivers/gpu/drm/ast/ast_dp501.c @@ -442,7 +442,7 @@ static void ast_init_analog(struct drm_d /* Finally, clear bits [17:16] of SCU2c */ data = ast_read32(ast, 0x1202c); data &= 0xfffcffff; - ast_write32(ast, 0, data); + ast_write32(ast, 0x1202c, data); /* Disable DVO */ ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xa3, 0xcf, 0x00);