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 4E22510F996A for ; Wed, 8 Apr 2026 18:34:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6B8FB10E6DC; Wed, 8 Apr 2026 18:34:15 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wT0mvxcW"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 19F1E10E6C4 for ; Wed, 8 Apr 2026 18:34:14 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id CFD4143856; Wed, 8 Apr 2026 18:34:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61FFFC2BC9E; Wed, 8 Apr 2026 18:34:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775673253; bh=0n1fdfU4NT53UkqRIKqnr4n8j24URz6o0xjHY10N8k0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wT0mvxcW+xLjRvUMDKVuxgEAAMLuerVdl1tfbeF7UaiuI6/NEv4aUT4tfnixKBxsR wFYRomWQx0gmtyaoIubDOcmz5Pd4YdeESOH53KvefC1JHszjeQLifbAuTyflIMvEOX Peh3oO5HF3rlrKlBUOQ5TTSMenQ/ShwTCMv2sE+U= 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 6.18 161/277] drm/ast: dp501: Fix initialization of SCU2C Date: Wed, 8 Apr 2026 20:02:26 +0200 Message-ID: <20260408175939.882053468@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175933.836769063@linuxfoundation.org> References: <20260408175933.836769063@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" 6.18-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 @@ -436,7 +436,7 @@ static void ast_init_analog(struct ast_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);