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 E46D8C88E5C for ; Wed, 16 Sep 2026 08:35:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6596610E851; Wed, 16 Sep 2026 08:35:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="TWkVvcnZ"; 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 6496C10E851; Wed, 16 Sep 2026 08:35:32 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3172C43BD1; Wed, 16 Sep 2026 08:35:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D26AD1F00893; Wed, 16 Sep 2026 08:35:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789547732; bh=W513gnMDYceLP2juk9l8h8B6cA+CtCxqvFG7ZW9cL+c=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=TWkVvcnZrp9vWb/jz+7uF346aS6qMrS6wzREbztQiMpb1eEQqKSRgKdtGrKKPgNny 83Gr4iJMZvGrxBPyZ8L/irKjFMEz5PKWb6pxu0rtdavbDmVjLP502yAMn0wlQ1LB4g mEPB8bHEqeO4C8qho2i5Emqg9V7DYCA/Z3FYRQlaIcn9VXYd3q70u/p+y+KHHzdqXU V6HxIS5B/zGKD7OmfzjDkPVbxiPm3SUbmdsPt8HA6lSjQelUgHWDI6/XmIw8WCmXNr hNLKJJKKru0TVMtNgr9ulCDPpQYA/j+CpcldsShCBcXAKCzgMd8eLHpucyPKwHnUFV 89RMUXBh1filA== From: sashiko-bot@kernel.org Subject: Re: [PATCH 07/11] drm/i915/hdcp: switch to drm_dp_dpcd_{read_byte, read_data, write_data}() To: "Jani Nikula" Cc: intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org In-Reply-To: References: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 16 Sep 2026 08:35:31 +0000 Message-Id: <20260916083531.D26AD1F00893@smtp.kernel.org> X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] drm/i915/hdcp: incorrect buffer advancement in intel_dp_hdcp2_read= _msg() -- commit ef5e2443a19df2b1333678ad805fe64be928f4df Author: Jani Nikula drm/i915/hdcp: switch to drm_dp_dpcd_{read_byte, read_data, write_data}() This commit switches DPCD accesses to modern functions that return 0 on suc= cess and negative error codes on failure. It simplifies error handling and conve= rts logging to use %pe and ERR_PTR(). > diff --git a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c b/drivers/gpu/d= rm/i915/display/intel_dp_hdcp.c > --- a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c [ ... ] > @@ -493,14 +493,13 @@ ssize_t get_receiver_id_list_rx_info(struct intel_c= onnector *connector, > { > struct intel_digital_port *dig_port =3D intel_attached_dig_port(connect= or); > struct drm_dp_aux *aux =3D &dig_port->dp.aux; > - ssize_t ret; > u8 *rx_info =3D byte; > + int ret; > =20 > - ret =3D drm_dp_dpcd_read(aux, > - DP_HDCP_2_2_REG_RXINFO_OFFSET, > - (void *)rx_info, HDCP_2_2_RXINFO_LEN); > - if (ret !=3D HDCP_2_2_RXINFO_LEN) > - return ret >=3D 0 ? -EIO : ret; > + ret =3D drm_dp_dpcd_read_data(aux, DP_HDCP_2_2_REG_RXINFO_OFFSET, > + rx_info, HDCP_2_2_RXINFO_LEN); > + if (ret < 0) > + return ret; [Severity: High] Will this return value cause issues for downstream topology authentication? Since drm_dp_dpcd_read_data() returns 0 on success (instead of the number of bytes read), get_receiver_id_list_rx_info() now returns 0 on success. Looking at the caller in intel_dp_hdcp2_read_msg(), it expects the return value to be the number of bytes read so it can advance the buffer pointer: if (msg_id =3D=3D HDCP_2_2_REP_SEND_RECVID_LIST) { ret =3D get_receiver_id_list_rx_info(connector, &dev_cnt, byte); if (ret < 0) return ret; byte +=3D ret; Since ret is 0, the pointer won't advance, which could cause the subsequent payload read to overwrite the rx_info field. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/cover.1789547331.gi= t.jani.nikula@intel.com?part=3D7