firmware_class: Refer to Debian wiki page when logging missing firmware

Closes: #888405

debian/changelog

@@ -13,6 +13,8 @@ linux (4.15.4-2) UNRELEASED; urgency=medium
     SND_SOC_INTEL_HASWELL, SND_SOC_INTEL_BAYTRAIL, SND_SST_ATOM_HIFI2_PLATFORM,
     SND_SOC_INTEL_SKYLAKE as modules; re-enable dependent board drivers
     (Closes: #892629)
+  * firmware_class: Refer to Debian wiki page when logging missing firmware
+    (Closes: #888405)
 
  -- Salvatore Bonaccorso <carnil@debian.org>  Tue, 20 Feb 2018 21:51:39 +0100
 

debian/patches/debian/firmware_class-refer-to-debian-wiki-firmware-page.patch

@@ -0,0 +1,28 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Mon, 12 Mar 2018 01:14:03 +0000
+Subject: firmware_class: Refer to Debian wiki page when logging missing firmware
+Bug-Debian: https://bugs.debian.org/888405
+Forwarded: not-needed
+
+If firmware loading fails due to a missing file, log a second error
+message referring to our wiki page about firmware.  This will explain
+why some firmware is in non-free, or can't be packaged at all.  Only
+do this once per boot.
+
+---
+--- a/drivers/base/firmware_class.c
++++ b/drivers/base/firmware_class.c
+@@ -430,9 +430,12 @@ fw_get_filesystem_firmware(struct device
+ 	}
+ 	__putname(path);
+ 
+-	if (rc)
++	if (rc) {
+ 		dev_err(device, "firmware: failed to load %s (%d)\n",
+ 			buf->fw_id, rc);
++		if (rc == -ENOENT)
++			pr_err_once("See https://wiki.debian.org/Firmware for information about missing firmware\n");
++	}
+ 
+ 	return rc;
+ }

debian/patches/series

@@ -15,6 +15,7 @@ debian/tools-perf-install.patch
 features/all/drivers-media-dvb-usb-af9005-request_firmware.patch
 debian/iwlwifi-do-not-request-unreleased-firmware.patch
 bugfix/all/firmware_class-log-every-success-and-failure.patch
+debian/firmware_class-refer-to-debian-wiki-firmware-page.patch
 bugfix/all/firmware-remove-redundant-log-messages-from-drivers.patch
 bugfix/all/radeon-firmware-is-required-for-drm-and-kms-on-r600-onward.patch