May 15th, 2020

Non-Hierarchical Taxonomies and JSON-LD Compatibility

While Breadcrumb NavXT for some time has provided methods for generating JSON-LD formatted BreadcrumbLists, the use of non-hierarchical taxonomies within a breadcrumb trail may result in non-compliant breadcrumb trails. For the case of a post only being a member of a single term within a non-hierarchical taxonomy, since Breadcrumb NavXT 6.4, compliant JSON-LD is generated. However, when a post is a member of multiple non-hierarchical terms within the same taxonomy, we run into problems.

When using the normal display functions, all of the terms in the non-hierarchical taxonomy that the post is a member of will be displayed, separated by commas. This behavior has been more-or-less the same since support for tags was added in 2.1.0. In essence, when there are multiple terms, there is a second dimension to the breadcrumb trail for that specific breadcrumb.

Unfortunately, it does not appear that Schema.org BreadcrumbList has the facility to support multi-dimensional breadcrumbs. Hence, a single term needs to be selected when there are multiple for a post. Luckily, the bcn_post_terms filter can be used to do this.

The Code

Introduced in Breadcrumb NavXT 5.4, bcn_post_terms allows us to filter out all of the terms returned by post_terms(). In this case, only the first term is wanted.

add_filter('bcn_post_terms','my_bcn_post_term_selector', 10, 3);
function my_bcn_post_term_selector($terms, $taxonomy, $id)
{
	//Check to ensure the terms list is an array and there is more than one item in it
	if(is_array($terms) and count($terms) > 1)
	{
		//Return the fist item in a new array
		return array(0 => reset($terms));
	}
	return $terms;
}

To get started quickly, just copy and paste the above code into a site specific plugin and start playing.

Note: This code relies on behavior introduced in Breadcrumb NavXT 6.4 and will not work in prior versions.

-John Havlik

May 22nd, 2019

Fix Missing Network Controllers on Windows 10 Build 18362 (19H1)

Posted by John Havlik in Guides

After being graced with the latest Windows 10 feature update, Build 18362, both network adapters on my ASRock X370 Taichi motherboard went missing. This was not a simple case of the drivers for the network cards, the Intel Wireless-AC 9260 and Intel I211, not being installed, device manager did not even have a “unknown device” placeholder for either NIC.

Luckily, this was not a hardware issue (failure). Both devices worked once again after rolling back the build 18362 update. However, this is not a long-term solution as Windows 10 is very persistent on nagging users to install feature updates.

As the hardware had not failed, it was on to looking for something missing in the PCIe tree. Unfortunately, Windows 10 does not ship something like lspci as most Linux distributions do. However, there is the Device Management PowerShell utility. With it installed, the following command can be used to collect the PCI tree:

Get-device | where {$_.LocationInfo -like 'PCI bus*'} | select Name, LocationInfo, UINumber > pci_tree.txt

Comparing the PCI tree from before and after the build 18362 update revealed that the “PCI Downstream Switch Ports” on PCI bus 38 and the “PCI Upstream Switch” port on PCI bus 13 were missing (along with the two Intel NICs). On the ASRock X370 Taichi, only the CPU and the chipset contain PCIe switches. Given that NICs are traditionally attached to the chipset, it was time to look at the chipset driver.

Attempting to re-install the latest AMD X370 chipset driver revealed that Windows had downgraded the driver in the feature update—breaking the PCI bus in the process. Fixing the issue was as simple as re-installing the AMD 19.10.0429 chipset driver. After a reboot, both NICs were working one again.

March 9th, 2019

Fix Linux Boot Halting on “Run /init as init process”

Posted by John Havlik in Guides

In the process of removing the remaining SandForce controller based SSDs from service, the opportunity to completely refresh the Funtoo install on the XPS 15 9530 was taken. Part of this was to try to figure out why recently sddm would not start until a bit of keyboard mashing occurred (literally pushing the enter key a dozen times in a row caused sddm to start, waiting was simply not enough).

The install was fairly painless—most problems tend to be involve getting the proper device drivers compiled into the kernel. Given there was already a known good kernel config, that was used for the building the kernel on the new install. However, on the first boot off of the new SSD, the boot process halted at:

[2.754164] Freeing unused kernel image memory: 1020K
[2.756196] Write protecting the kernel read-only data: 20480k
[2.758698] Freeing unused kernel image memory: 1980K
[2.760892] Freeing unused kernel image memory: 620K
[2.764980] Run /sbin/init as init process

The init system (OpenRC), for some reason, did not actually kick off. Plugging in a USB device confirmed that the kernel itself was still running. Thus, it was not something simple such as the root device being inaccessible (that causes a kernel panic). But, in this state, the system was not usable (no login prompt).

After a bit of sleuthing and stumbling, a solution was found. The following was added to the kernel config:

CONFIG_DEVTMPFS_MOUNT=y

After rebuilding the kernel and rebooting, the system finally booted completely. Still, this is a little unnerving. This machine never needed this setting before. Additionally, I have not needed this setting on any other machine.

November 30th, 2018

Breadcrumb NavXT and Bootstrap 4 Breadcrumb

Posted by John Havlik in Guides

Out of the box Breadcrumb NavXT generates markup that is ready for Schema.org BreadcrumbList compliance. While this is great for most cases, for users of frameworks, some markup changes may be desireable. This article looks at what is necessary to get Breadcrumb NavXT to generate markup compliant with Bootstrap 4’s Breadcrumb component.

The Code

To generate Bootstrap 4 breadcrumb compliant markup, two bits of code are needed. The first is the appropriate calling code (including the proper wrapping markup). Place the following calling code in the appropriate theme file(s) (usually header.php):

<?php if(function_exists('bcn_display_list')):?>
<nav class="breadcrumbs" typeof="BreadcrumbList" vocab="https://schema.org/" aria-label="breadcrumb">
    <ol class="breadcrumb">
        <?php bcn_display_list();?>
    </ol>
</nav>
<?php endif; ?>

The second bit of code goes into a site specific plugin:

add_filter('bcn_display_attributes', my_display_attributes_filter, 10, 3);
function my_display_attributes_filter($attribs, $types, $id)
{
    $extra_attribs = array('class' => array('breadcrumb-item'));
    //For the current item we need to add a little more info
    if(is_array($types) && in_array('current-item', $types))
    {
        $extra_attribs['class'][] = 'active';
        $extra_attribs['aria-current'] = array('page');
    }
    $atribs_array = array();
    preg_match_all('/([a-zA-Z]+)=["\']([a-zA-Z0-9\-\_ ]*)["\']/i', $attribs, $matches);
    if(isset($matches[1]))
    {
        foreach ($matches[1] as $key => $tag)
        {
            if(isset($matches[2][$key]))
            {
                $atribs_array[$tag] = explode(' ', $matches[2][$key]);
            }
        }
    }
    $merged_attribs = array_merge_recursive($atribs_array , $extra_attribs);
    $output = '';
    foreach($merged_attribs as $tag => $vals)
    {
        $output .= sprintf(' %1$s="%2$s"', $tag, implode(' ', $vals));
    }
    return $output;
}

This code adds the breadcrumb-item to every breadcrumb in the trail. Additionally it adds the active class and the arria-current attribute to the current item. While the first could be easily achieved by updating every Breadcrumb template, this solution is easier to implement and allows us to use bcn_display_list().

Unfortunately, the bcn_display_attributes filter available since Breadcrumb NavXT 6.0 is not the easiest use in an efficient and robust manner. In the future a new filter will be added to address this deficiency. As presented, my_display_attributes_filter will be greatly simplified with said new filter (lines 11-22 and 24-28 go away). This article will be updated at that time to reflect the changes in API.

-John Havlik

[end of transmission, stay tuned]

November 2nd, 2018

Fix Bluetooth Mouse Pairing but not Moving Cursor in Linux

Posted by John Havlik in Guides

I recently picked up a Logitech M585 to replace my old M577 which was randomly registering multiple clicks for each left click. This was the second button to go bad on that mouse so it was time for an upgrade (the back click action on the mouse wheel had gone out a year back).

While I had no problems pairing the M585 with my laptop running Linux, it was not moving the cursor and mouse clicks were not registering. This is not the first mouse that I’ve had issues with on this laptop, the Microsoft Bluetooth Mobile Mouse 3600 exhibited a similar behavior. Checking the system logs, I found the following clue:

[bluetoothd] input-hog profile accept failed for XX:XX:XX:XX:XX:XX

Where XX:XX:XX:XX:XX:XX is the bluetooth address for the mouse. After some digging, I came across the solution. CONFIG_UHID needs to be set to ‘y’ in the kernel config to enable userspace I/O driver support for the HID subsystem.

CONFIG_UHID=y

After making this change, recompiling the kernel and rebooting the M585 pairs and works properly as a mouse. Additionally, the MS Bluetooth Mobile Mouse 3600 now works properly as well.

-John Havlik

[end of transmission, stay tuned]