Re: [igt-dev] [PATCH v2] tests/i915_pm_rpm: improved strictness and verbosity of i2c subtest

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jun 13, 2019 at 04:06:23PM +0300, Oleg Vasilev wrote:
> Test checked that the number of valid edids from drm is equal to the
> same number from i2c.
> 
> Now for each edid the whole blob is compared. In case of mismatch the
> whole edid is printed.
> 
> v2:
>  - Improved messages in order to set up CI filter
>  - Log and clear errno in case of i2c failure
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104097
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
> Cc: Martin Peres <martin.peres@linux.intel.com>
> Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
> ---
>  tests/i915/i915_pm_rpm.c | 180 ++++++++++++++++++++++++---------------
>  1 file changed, 112 insertions(+), 68 deletions(-)
> 
> diff --git a/tests/i915/i915_pm_rpm.c b/tests/i915/i915_pm_rpm.c
> index f9f67ed3..87140e30 100644
> --- a/tests/i915/i915_pm_rpm.c
> +++ b/tests/i915/i915_pm_rpm.c
> @@ -572,33 +572,55 @@ static void assert_drm_infos_equal(struct compare_data *d1,
>  		assert_drm_crtcs_equal(d1->crtcs[i], d2->crtcs[i]);
>  }
>  
> -/* We could check the checksum too, but just the header is probably enough. */
> -static bool edid_is_valid(const unsigned char *edid)
> +static bool find_i2c_path(char *connector_name, char *i2c_path)

const char *connector_name

>  {
> -	char edid_header[] = {
> -		0x0, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0,
> -	};
> +	struct dirent *dirent;
> +	DIR *dir;
> +	int sysfs_card_fd = igt_sysfs_open(drm_fd);
> +	int connector_fd = -1;
> +	bool found_i2c_file = false;
>  
> -	return (memcmp(edid, edid_header, sizeof(edid_header)) == 0);
> -}
> +	dir = fdopendir(sysfs_card_fd);
> +	igt_assert(dir);
>  
> -static int count_drm_valid_edids(struct mode_set_data *data)
> -{
> -	int ret = 0;
> +	while ((dirent = readdir(dir))) {
> +		/* Skip "cardx-" prefix */
> +		char *dirname = dirent->d_name;
> +		while(dirname[0] != '\0' && dirname[0] != '-')
> +			++dirname;
> -	if (!data->res)
> -		return 0;
> +		if(*dirname == '-')
> +			++dirname;

dirname = dirent->d_name;
strsep(&dirname, "-");
dirname = dirname ?: dirent->d_name;

or

dirname = strchr(dirent->d_name, '-');
dirname = dirname ? dirname + 1 : dirent->d_name;

?

>  
> -	for (int i = 0; i < data->res->count_connectors; i++)
> -		if (data->edids[i] && edid_is_valid(data->edids[i]->data))
> -			ret++;
> -	return ret;
> +		if (strcmp(dirname, connector_name) == 0) {
> +			connector_fd = openat(sysfs_card_fd, dirent->d_name, O_RDONLY);
> +			break;
> +		}
> +	}
> +	closedir(dir);
> +
> +	if(connector_fd < 0)
> +		return false;
> +
> +	dir = fdopendir(connector_fd);
> +	igt_assert(dir);
> +
> +	while ((dirent = readdir(dir))) {
> +		if (strncmp(dirent->d_name, "i2c-", 4) == 0) {
> +			sprintf(i2c_path, "/dev/%s", dirent->d_name);
> +			found_i2c_file = true;
> +		}
> +	}
> +	closedir(dir);
> +	return found_i2c_file;
>  }
>  
> -static bool i2c_edid_is_valid(int fd)
> +
> +static bool i2c_read_edid(char *connector_name, unsigned char *edid)
>  {
> -	int rc;
> -	unsigned char edid[128] = {};
> +	char i2c_path[PATH_MAX];
> +	bool result = find_i2c_path(connector_name, i2c_path);
> +	int rc, fd;
>  	struct i2c_msg msgs[] = {
>  		{ /* Start at 0. */
>  			.addr = 0x50,
> @@ -617,69 +639,91 @@ static bool i2c_edid_is_valid(int fd)
>  		.nmsgs = 2,
>  	};
>  

I would put the
result = find_i2c_path(connector_name, i2c_path);

here because it's a nasty function with side effects. So IMO
shouldn't be hidden in the declaration block.

> +	if (!result)
> +		return false;
> +
> +	fd = open(i2c_path, O_RDWR);
> +	igt_assert_neq(fd, -1);
> +
>  	rc = ioctl(fd, I2C_RDWR, &msgset);
> -	return (rc >= 0) ? edid_is_valid(edid) : false;
> +	if(rc==-1){
> +		igt_debug("I2C access failed with errno %d, %s\n",
> +				errno, strerror(errno));
> +		errno = 0;
> +	}
> +
> +	close(fd);
> +	return rc >= 0;
>  }
>  
> -static int count_i2c_valid_edids(void)
> +static void format_hex_string(unsigned char edid[static EDID_LENGTH],
> +			      char buf[static EDID_LENGTH * 5 + 1])

What's the deal with those 'static's?

'edid' can be const.

>  {
> -	int fd, ret = 0;
> -	DIR *dir;
> +	for (size_t i = 0; i < EDID_LENGTH; ++i)

I'm not a fan of 'i' which is not int. Most people would expect
it to be signed int so I would recommend against using 'i'
when you have some other type. In this case 'int' should
do just fine I think.

> +		sprintf(buf+i*5, "0x%02x ", edid[i]);
> +}
>  
> -	struct dirent *dirent;
> -	char full_name[PATH_MAX];
> +static void test_i2c(struct mode_set_data *data)
> +{
> +	bool edid_mistmach_i2c_vs_drm = false;
> +	igt_display_t display;
> +	igt_display_require(&display, drm_fd);
>  
> -	dir = opendir("/dev/");
> -	igt_assert(dir);
> +	for (int i = 0; i < data->res->count_connectors; i++) {
> +		unsigned char *drm_edid = data->edids[i] ? data->edids[i]->data : NULL;
> +		unsigned char i2c_edid[EDID_LENGTH] = {};
>  
> -	while ((dirent = readdir(dir))) {
> -		if (strncmp(dirent->d_name, "i2c-", 4) == 0) {
> -			sprintf(full_name, "/dev/%s", dirent->d_name);
> -			fd = open(full_name, O_RDWR);
> -			igt_assert_neq(fd, -1);
> -			if (i2c_edid_is_valid(fd))
> -				ret++;
> -			close(fd);
> -		}
> -	}
> +		igt_output_t *output = igt_output_from_connector(&display,
> +								 data->connectors[i]);
> +		char *connector_name = (char *) igt_output_name(output);
>  
> -	closedir(dir);
> +		bool got_i2c_edid = i2c_read_edid(connector_name, i2c_edid);
> +		bool got_drm_edid = drm_edid != NULL;
> +		bool is_vga = data->connectors[i]->connector_type == DRM_MODE_CONNECTOR_VGA;
>  
> -	return ret;
> -}
> +		bool edids_equal;
>  
> -static int count_vga_outputs(struct mode_set_data *data)
> -{
> -	int count = 0;
> +		/* We fail to detect some VGA monitors using our i2c method. If you look
> +		 * at the dmesg of these cases, you'll see the Kernel complaining about
> +		 * the EDID reading mostly FFs and then disabling bit-banging. Since we
> +		 * don't want to reimplement everything the Kernel does, let's just
> +		 * accept the fact that some VGA outputs won't be properly detected. */
> +		if(is_vga)
> +			continue;
>  
> -	if (!data->res)
> -		return 0;
> +		if(!got_i2c_edid && !got_drm_edid)
> +			continue;
> +
> +		if(got_i2c_edid && got_drm_edid)
> +			edids_equal = (0 == memcmp(drm_edid, i2c_edid, EDID_LENGTH));
> +		else
> +			edids_equal = false;
>  
> -	for (int i = 0; i < data->res->count_connectors; i++)
> -		if (data->connectors[i]->connector_type ==
> -		    DRM_MODE_CONNECTOR_VGA)
> -			count++;
>  
> -	return count;
> -}
> +		if (!edids_equal) {
> +			char buf[5 * EDID_LENGTH + 1];
> +			igt_critical("Detected EDID mismatch on connector %s\n",
> +				     connector_name);
>  
> -static void test_i2c(struct mode_set_data *data)
> -{
> -	int i2c_edids = count_i2c_valid_edids();
> -	int drm_edids = count_drm_valid_edids(data);
> -	int vga_outputs = count_vga_outputs(data);
> -	int diff;
> -
> -	igt_debug("i2c edids:%d drm edids:%d vga outputs:%d\n",
> -		  i2c_edids, drm_edids, vga_outputs);
> -
> -	/* We fail to detect some VGA monitors using our i2c method. If you look
> -	 * at the dmesg of these cases, you'll see the Kernel complaining about
> -	 * the EDID reading mostly FFs and then disabling bit-banging. Since we
> -	 * don't want to reimplement everything the Kernel does, let's just
> -	 * accept the fact that some VGA outputs won't be properly detected. */
> -	diff = drm_edids - i2c_edids;
> -	igt_assert(diff <= vga_outputs && diff >= 0);
> +			if(got_i2c_edid)
> +				format_hex_string(i2c_edid, buf);
> +			else
> +				sprintf(buf, "NULL");
> +
> +			igt_critical("i2c: %s\n", buf);
> +
> +			if(got_drm_edid)
> +				format_hex_string(drm_edid, buf);
> +			else
> +				sprintf(buf, "NULL");
> +
> +			igt_critical("drm: %s\n", buf);
> +
> +			edid_mistmach_i2c_vs_drm = true;
> +		}
> +	}
> +	igt_fail_on_f(edid_mistmach_i2c_vs_drm,
> +			"There is an EDID mismatch between i2c and DRM!\n");

The kernel does modify the reported EDID for some quirks IIRC. I don't
really like that behaviour, and it would be an issue for this test. But
I guess we don't have any of those on any monitors we test.

Apart from the minor nits looks good to me.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>


>  }
>  
>  static void setup_pc8(void)
> -- 
> 2.21.0

-- 
Ville Syrjälä
Intel
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