From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD959324B1F; Wed, 8 Apr 2026 18:24:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672641; cv=none; b=lOE9NT//vjNfFosIh+uhLrhkxjsE5EmfRIawYnEjNFa2yV8J1dH3ix05435R5p21ZCjQ8zwIhteXPCFuRZrcMpvnzXMEpm/Kc9kklr74ITeXImJbKTKuZ0N0j2Gn7IMNd7RdZ2FlQr8g+adba8M0/LKY7G3tBSQ5IrG8W9Mnxik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672641; c=relaxed/simple; bh=hggNYybW0V7L++/9nh5HQSAic/bEDbew7+2vWRvkeC8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uqyUjia00uqVQB+DfAmkbynF4VsPZ/qNMiN37Bs8yx6JdaYorBKm7f7pHlBiLVJSxzEwY9MYGnnH1qRw6JICGDHkRmPLFX1enGm/gbsPfxWyqNwjZ6Zl0w67MJ6jIdGTaZgc9bChfW48IbplnSv2HT3XM1MsD70edXCx23LG/DI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rXjaROkZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rXjaROkZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44377C19421; Wed, 8 Apr 2026 18:24:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775672641; bh=hggNYybW0V7L++/9nh5HQSAic/bEDbew7+2vWRvkeC8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rXjaROkZOMhKCrOycLGXzOkoYNkzAqrtC0h36yt8KF9YqFU1jR3Dj8K9dHE07Z6JV e60IWo4hhT91gwfiqJG/E9RJ9w1xqD52AqWLgmZzFXgVtI6jrB7rC4JrvBPb4xnCgN WZE4jQdR3K6jkDdIoH6Av3J7OoPKQqVFQ2vzfrlQ= 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 6.6 085/160] drm/ast: dp501: Fix initialization of SCU2C Date: Wed, 8 Apr 2026 20:02:52 +0200 Message-ID: <20260408175916.369983519@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175913.177092714@linuxfoundation.org> References: <20260408175913.177092714@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 @@ -439,7 +439,7 @@ 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_CRTC_PORT, 0xa3, 0xcf, 0x00);