Re: [igt-dev] [PATCH i-g-t 1/3] lib/tests/igt_edid: introduce EDID sanity checks

[Martin Peres <martin.peres@linux.intel.com>]

On 27/05/2019 15:03, Simon Ser wrote:
> The idea is to make sure we don't completely break EDIDs by performing some
> basic sanity-checking in lib tests.
> 
> The test currently only checks the base and alt EDIDs. More EDIDs will be added
> in the future: HDMI audio, 4K, 3D and so on.
> 
> The logic is mostly borrowed from lib/tests/igt_hdmi_inject.c. This patch is
> part of the "let's unify igt_edid and igt_hdmi_inject" series.

Reviewed-by: Martin Peres <martin.peres@linux.intel.com>
> 
> Signed-off-by: Simon Ser <simon.ser@intel.com>
> ---
>  lib/tests/igt_edid.c  | 96 +++++++++++++++++++++++++++++++++++++++++++
>  lib/tests/meson.build |  1 +
>  2 files changed, 97 insertions(+)
>  create mode 100644 lib/tests/igt_edid.c
> 
> diff --git a/lib/tests/igt_edid.c b/lib/tests/igt_edid.c
> new file mode 100644
> index 000000000000..6cf6b5c14b53
> --- /dev/null
> +++ b/lib/tests/igt_edid.c
> @@ -0,0 +1,96 @@
> +/*
> + * Copyright © 2019 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Authors: Simon Ser <simon.ser@intel.com>
> + */
> +
> +#include "config.h"
> +
> +#include <stdbool.h>
> +
> +#include "igt_core.h"
> +#include "igt_kms.h"
> +#include "igt_edid.h"
> +
> +static const unsigned char edid_header[] = {
> +	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00
> +};
> +
> +/**
> + * Sanity check the header of the base EDID block.
> + */
> +static bool edid_header_is_valid(const unsigned char *raw_edid)
> +{
> +	size_t i;
> +
> +	for (i = 0; i < sizeof(edid_header); i++)
> +		if (raw_edid[i] != edid_header[i])
> +			return false;
> +
> +	return true;
> +}
> +
> +/**
> + * Sanity check the checksum of the EDID block.
> + */
> +static bool edid_block_checksum(const unsigned char *raw_edid)
> +{
> +	size_t i;
> +	unsigned char csum = 0;
> +
> +	for (i = 0; i < EDID_LENGTH; i++) {
> +		csum += raw_edid[i];
> +	}
> +
> +	return csum == 0;
> +}
> +
> +typedef const unsigned char *(*get_edid_func)(void);
> +
> +igt_simple_main
> +{
> +	const struct {
> +		const char *desc;
> +		get_edid_func f;
> +		size_t exts;
> +	} funcs[] = {
> +		{ "base", igt_kms_get_base_edid, 0 },
> +		{ "alt", igt_kms_get_alt_edid, 0 },
> +		{0},
> +	}, *f;
> +	const unsigned char *edid;
> +	size_t i;
> +
> +	for (f = funcs; f->f; f++) {
> +		edid = f->f();
> +
> +		igt_assert_f(edid_header_is_valid(edid),
> +			     "invalid header on %s EDID", f->desc);
> +		/* check base edid block */
> +		igt_assert_f(edid_block_checksum(edid),
> +			     "checksum failed on %s EDID", f->desc);
> +		/* check extension blocks, if any */
> +		for (i = 0; i < f->exts; i++)
> +			igt_assert_f(edid_block_checksum(edid + (i + 1) * EDID_LENGTH),
> +				     "CEA block checksum failed on %s EDID", f->desc);
> +	}
> +}
> diff --git a/lib/tests/meson.build b/lib/tests/meson.build
> index 9950bd59c174..e5f369f743fa 100644
> --- a/lib/tests/meson.build
> +++ b/lib/tests/meson.build
> @@ -3,6 +3,7 @@ lib_tests = [
>  	'igt_can_fail',
>  	'igt_can_fail_simple',
>  	'igt_conflicting_args',
> +	'igt_edid',
>  	'igt_exit_handler',
>  	'igt_fork',
>  	'igt_fork_helper',
> 
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