diff --git a/gnu/build/linux-modules.scm b/gnu/build/linux-modules.scm
index 4a6d4ff08..251095072 100644
--- a/gnu/build/linux-modules.scm
+++ b/gnu/build/linux-modules.scm
@@ -20,6 +20,7 @@
 (define-module (gnu build linux-modules)
   #:use-module (guix elf)
   #:use-module (guix glob)
+  #:use-module (guix build utils)
   #:use-module (guix build syscalls)
   #:use-module (rnrs io ports)
   #:use-module (rnrs bytevectors)
@@ -40,7 +41,8 @@
 
             device-module-aliases
             known-module-aliases
-            matching-modules))
+            matching-modules
+            needed-modules))
 
 ;;; Commentary:
 ;;;
@@ -370,4 +372,25 @@ ALIAS is a string like \"scsi:t-0x00\" as returned by
                       module)))
               known-aliases))
 
+(define (system-device-aliases)
+  "Browse /sys/devices in search of \"modalias\" files and return the list of
+device aliases for the current system."
+  (let ((files (find-files "/sys/devices"
+                           (lambda (file stat)
+                             (and (eq? 'regular (stat:type stat))
+                                  (string=? "modalias" (basename file)))))))
+    (filter-map (lambda (file)
+                  (match (string-trim-right
+                          (call-with-input-file file get-string-all))
+                    ("" #f)
+                    (alias alias)))
+                files)))
+
+(define* (needed-modules #:optional (known-aliases (known-module-aliases)))
+  "Return the list of modules needed by devices on the current system.  This
+is achieved by browsing /sys/devices and returning the maching modules from
+KNOWN-ALIASES."
+  (append-map (cut matching-modules <> known-aliases)
+              (system-device-aliases)))
+
 ;;; linux-modules.scm ends here