No matching global declaration available for the validation root

Question

Background

Validate an XML document using a schema.

Problem

The simplest form of the problem is shown in two files.

XML Document

<?xml version="1.0"?>

<recipe
  xmlns:r="http://www.namespace.org/recipe">

<r:description>
  <r:title>sugar cookies</r:title>
</r:description>

</recipe>

XSD Document

<?xml version="1.0" encoding="utf-8"?>
<xsd:schema
   version="1.0"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   xmlns:r="http://www.namespace.org/recipe">

  <xsd:complexType name="recipe">
    <xsd:choice>
      <xsd:element name="description" type="descriptionType"
        minOccurs="1" maxOccurs="1" />
    </xsd:choice>
  </xsd:complexType>

  <xsd:complexType name="descriptionType">
    <xsd:all>
      <xsd:element name="title">
        <xsd:simpleType>
          <xsd:restriction base="xsd:string">
            <xsd:minLength value="5" />
            <xsd:maxLength value="55" />
          </xsd:restriction>
        </xsd:simpleType>
      </xsd:element>
    </xsd:all>
  </xsd:complexType>
</xsd:schema>

Error

The full error message from xmllint:

file.xml:4: element recipe: Schemas validity error : Element 'recipe': No matching global declaration available for the validation root.

Question

What is the correct syntax (or what schema attributes are missing) to ensure that the given schema can be used to successfully validate the given XML document?