From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-vbr15.xs4all.nl ([194.109.24.35]:1731 "EHLO smtp-vbr15.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753323Ab3LQNPZ (ORCPT ); Tue, 17 Dec 2013 08:15:25 -0500 Message-ID: <52B04DF2.3020601@xs4all.nl> Date: Tue, 17 Dec 2013 14:13:22 +0100 From: Hans Verkuil MIME-Version: 1.0 To: linux-media@vger.kernel.org CC: Martin Bugge , Hans Verkuil Subject: [RFC PATCH 7/6] adv7511: verify EDID header References: <1386677334-20953-1-git-send-email-hverkuil@xs4all.nl> <9e6b2a84d52136da9f7f8ec66186e659de5a0230.1386677238.git.hans.verkuil@cisco.com> In-Reply-To: <9e6b2a84d52136da9f7f8ec66186e659de5a0230.1386677238.git.hans.verkuil@cisco.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Ignore EDID's where the header is wrong. Signed-off-by: Martin Bugge Signed-off-by: Hans Verkuil --- drivers/media/i2c/adv7511.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/drivers/media/i2c/adv7511.c b/drivers/media/i2c/adv7511.c index f20450c..ee61894 100644 --- a/drivers/media/i2c/adv7511.c +++ b/drivers/media/i2c/adv7511.c @@ -965,26 +965,38 @@ static void adv7511_check_monitor_present_status(struct v4l2_subdev *sd) static bool edid_block_verify_crc(uint8_t *edid_block) { - int i; uint8_t sum = 0; + int i; for (i = 0; i < 128; i++) - sum += *(edid_block + i); - return (sum == 0); + sum += edid_block[i]; + return sum == 0; } -static bool edid_segment_verify_crc(struct v4l2_subdev *sd, u32 segment) +static bool edid_verify_crc(struct v4l2_subdev *sd, u32 segment) { struct adv7511_state *state = get_adv7511_state(sd); u32 blocks = state->edid.blocks; uint8_t *data = state->edid.data; - if (edid_block_verify_crc(&data[segment * 256])) { - if ((segment + 1) * 2 <= blocks) - return edid_block_verify_crc(&data[segment * 256 + 128]); + if (!edid_block_verify_crc(&data[segment * 256])) + return false; + if ((segment + 1) * 2 <= blocks) + return edid_block_verify_crc(&data[segment * 256 + 128]); + return true; +} + +static bool edid_verify_header(struct v4l2_subdev *sd, u32 segment) +{ + static const u8 hdmi_header[] = { + 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 + }; + struct adv7511_state *state = get_adv7511_state(sd); + u8 *data = state->edid.data; + + if (segment != 0) return true; - } - return false; + return !memcmp(data, hdmi_header, sizeof(hdmi_header)); } static bool adv7511_check_edid_status(struct v4l2_subdev *sd) @@ -1013,9 +1025,10 @@ static bool adv7511_check_edid_status(struct v4l2_subdev *sd) state->edid.blocks = state->edid.data[0x7e] + 1; v4l2_dbg(1, debug, sd, "%s: %d blocks in total\n", __func__, state->edid.blocks); } - if (!edid_segment_verify_crc(sd, segment)) { + if (!edid_verify_crc(sd, segment) || + !edid_verify_header(sd, segment)) { /* edid crc error, force reread of edid segment */ - v4l2_dbg(1, debug, sd, "%s: edid crc error\n", __func__); + v4l2_err(sd, "%s: edid crc or header error\n", __func__); state->have_monitor = false; adv7511_s_power(sd, false); adv7511_s_power(sd, true); -- 1.8.4.rc3