[Intel-gfx] [PATCH i-g-t] tests/pm_backlight: Add backlight test

[Antti Koskipää]

On 05/26/2015 02:37 PM, Jani Nikula wrote:
> On Sat, 23 May 2015, Antti Koskipaa <antti.koskipaa at linux.intel.com> wrote:
>> This is a basic sanity test of the backlight sysfs interface.
>>
>> Issue: VIZ-3377
>> Signed-off-by: Antti Koskipaa <antti.koskipaa at linux.intel.com>
>> ---
>>  tests/.gitignore       |   1 +
>>  tests/Makefile.sources |   1 +
>>  tests/pm_backlight.c   | 144 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 146 insertions(+)
>>  create mode 100644 tests/pm_backlight.c
>>
>> diff --git a/tests/.gitignore b/tests/.gitignore
>> index a3f3143..f816ded 100644
>> --- a/tests/.gitignore
>> +++ b/tests/.gitignore
>> @@ -150,6 +150,7 @@ kms_vblank
>>  kms_crtc_background_color
>>  kms_plane_scaling
>>  kms_panel_fitting
>> +pm_backlight
>>  pm_lpsp
>>  pm_rc6_residency
>>  pm_rpm
>> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
>> index 994c31b..d2a44e8 100644
>> --- a/tests/Makefile.sources
>> +++ b/tests/Makefile.sources
>> @@ -80,6 +80,7 @@ TESTS_progs_M = \
>>  	kms_crtc_background_color \
>>  	kms_plane_scaling \
>>  	kms_panel_fitting \
>> +	pm_backlight \
>>  	pm_lpsp \
>>  	pm_rpm \
>>  	pm_rps \
>> diff --git a/tests/pm_backlight.c b/tests/pm_backlight.c
>> new file mode 100644
>> index 0000000..eb2dcf5
>> --- /dev/null
>> +++ b/tests/pm_backlight.c
>> @@ -0,0 +1,144 @@
>> +/*
>> + * Copyright © 2015 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.
>> + *
>> + * Author:
>> + *    Antti Koskipaa <antti.koskipaa at linux.intel.com>
>> + *
>> + */
>> +
>> +#include <limits.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +#include <fcntl.h>
>> +#include <stdio.h>
>> +#include <errno.h>
>> +#include <unistd.h>
>> +
>> +#include "igt_core.h"
>> +
>> +#define TOLERANCE 5 /* percent */
>> +#define BACKLIGHT_PATH "/sys/class/backlight/intel_backlight"
>> +
>> +IGT_TEST_DESCRIPTION("Basic backlight sysfs test");
>> +
>> +static int backlight_read(int *result, const char *fname)
>> +{
>> +	int fd;
>> +	char full[PATH_MAX];
>> +	char dst[64];
>> +	int r, e;
>> +
>> +	igt_assert(snprintf(full, PATH_MAX, "%s/%s", BACKLIGHT_PATH, fname) < PATH_MAX);
>> +
>> +	fd = open(full, O_RDONLY);
>> +	if (fd == -1)
>> +		return -errno;
>> +
>> +	r = read(fd, dst, sizeof(dst));
>> +	e = errno;
>> +	close(fd);
>> +
>> +	if (r < 0)
>> +		return -e;
>> +
>> +	errno = 0;
>> +	*result = strtol(dst, NULL, 10);
>> +	return errno;
>> +}
>> +
>> +static int backlight_write(int value, const char *fname)
>> +{
>> +	int fd;
>> +	char full[PATH_MAX];
>> +	char src[64];
>> +	int len;
>> +
>> +	igt_assert(snprintf(full, PATH_MAX, "%s/%s", BACKLIGHT_PATH, fname) < PATH_MAX);
>> +	fd = open(full, O_WRONLY);
>> +	if (fd == -1)
>> +		return -errno;
>> +
>> +	len = snprintf(src, sizeof(src), "%i", value);
>> +	len = write(fd, src, len);
>> +	close(fd);
>> +
>> +	if (len < 0)
>> +		return len;
>> +
>> +	return 0;
>> +}
>> +
>> +static void test_and_verify(int val, int max)
>> +{
>> +	int result;
>> +	igt_assert(backlight_write(val, "brightness") == 0);
>> +	igt_assert(backlight_read(&result, "actual_brightness") == 0);
>> +	/* Some rounding may happen depending on hw. Just check that it's close enough. */
>> +	igt_assert(result <= val + val * TOLERANCE / 100 && result >= val - val * TOLERANCE / 100);
> 
> This could additionally read "brightness" and assert it is equal to what
> was just written (i.e. without the tolerance check).

v2 coming soon.

> There are no guarantees that the result read back from
> "actual_brightness" would be within the tolerance, in fact it could be
> changed by ACPI behind our backs, at least on some platforms... But I
> guess this is good enough.

It should be, unless the tester does something stupid like slam the lid
shut in the middle of the test or something.

>> +}
>> +
>> +static void test_brightness(int max)
>> +{
>> +	test_and_verify(0, max);
>> +	test_and_verify(max, max);
>> +	test_and_verify(max / 2, max);
>> +}
> 
> A followup could add a test to fade both ways using a loop; can be a
> follow-up later on.

Will implement in v2, if the backlight responds sensibly.

> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
> 
> 
> 
> BR,
> Jani.
> 
>> +
>> +static void test_bad_brightness(int max)
>> +{
>> +	int val;
>> +	/* First write some sane value */
>> +	backlight_write(max / 2, "brightness");
>> +	/* Writing invalid values should fail and not change the value */
>> +	igt_assert(backlight_write(-1, "brightness") < 0);
>> +	backlight_read(&val, "brightness");
>> +	igt_assert(val == max / 2);
>> +	igt_assert(backlight_write(max + 1, "brightness") < 0);
>> +	backlight_read(&val, "brightness");
>> +	igt_assert(val == max / 2);
>> +	igt_assert(backlight_write(INT_MAX, "brightness") < 0);
>> +	backlight_read(&val, "brightness");
>> +	igt_assert(val == max / 2);
>> +}
>> +
>> +igt_main
>> +{
>> +	int max, old;
>> +
>> +	igt_skip_on_simulation();
>> +
>> +	igt_fixture {
>> +		/* Get the max value and skip the whole test if sysfs interface not available */
>> +		igt_skip_on(backlight_read(&old, "brightness"));
>> +		igt_assert(backlight_read(&max, "max_brightness") > -1);
>> +	}
>> +
>> +	igt_subtest("brightness")
>> +		test_brightness(max);
>> +	igt_subtest("bad-brightness")
>> +		test_bad_brightness(max);
>> +
>> +	igt_fixture {
>> +		/* Restore old brightness */
>> +		backlight_write(old, "brightness");
>> +	}
>> +}
>> -- 
>> 1.8.3.2
>>
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>