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* PATCHES: Device discovery of the "bluetooth" CUPS backend does not work
@ 2009-08-10 20:19 Till Kamppeter
  2009-08-11 10:33 ` Bastien Nocera
  0 siblings, 1 reply; 12+ messages in thread
From: Till Kamppeter @ 2009-08-10 20:19 UTC (permalink / raw)
  To: linux-bluetooth

Hi,

I am using Bluez 4.47, and I can set up a Bluetooth printer only 
manually by running the "bluetooth" CUPS backend from the command line with

/usr/lib/cups/backend/bluetooth

and then pasting the URI into the field for individual URI input in 
system-config-printer ("Others" in the device list). Then I also need to 
choose manufacturer and model manually. My expectation is that I only 
need to click the printer's make model name in the devices list and 
choose "Bluetooth" under the connection types and then the driver gets 
selected automatically as it is the case for the same printer on USB or 
WLAN.

I have found out why it does not work.

First, the CUPS Bluetooth backend asks the bluez D-Bus service whether 
there are printers available and which device ID they have. The access 
permissions for the bluez D-Bus service do not permit the CUPS system 
user "lp" to access, and exactly as this user the Bluetooth backend is 
running. Therefore I have modified /etc/dbus-1/system.d/bluetooth.conf 
to grant this permission.

I have added the following lines into the <busconfig> section:


   <!-- allow users of lp group (printing subsystem) to communicate with 
hcid -->
   <policy group="lp">
     <allow send_destination="org.bluez"/>
   </policy>


Second, the output of the CUPS Bluetooth backend was not very good for 
the printer setup tools doing the right thing. I have patched the 
backend to let the device class of the Bluetooth printers to be "direct" 
and not "network", as users expect a Bluetooth printer rather under the 
local printers than under the network printers. I have also filled the 
make-and-model field instead of putting a hard-coded "Unknown" there. 
The change is here:


--- bluez-4.47/cups/main.c	2009-07-03 00:43:14.000000000 +0200
+++ bluez-4.47.new/cups/main.c	2009-08-10 20:09:32.000000000 +0200
@@ -226,7 +226,7 @@
  		 bdaddr[9], bdaddr[10],
  		 bdaddr[12], bdaddr[13],
  		 bdaddr[15], bdaddr[16]);
-	printf("network %s \"Unknown\" \"%s (Bluetooth)\"", uri, escaped);
+	printf("direct %s \"%s\" \"%s (Bluetooth)\"", uri, escaped, escaped);
  	if (id != NULL)
  		printf(" \"%s\"\n", id);
  	else


See also my Ubuntu bug report:

https://bugs.launchpad.net/bugs/411610

I am very grateful if you could apply these changes to Bluez upstream, 
as this makes the bluetooth CUPS backend just work.

Thank you very much in advance.

    Till


http://www.openprinting.org/


^ permalink raw reply	[flat|nested] 12+ messages in thread
* PATCHES: Device discovery of the "bluetooth" CUPS backend does not work
@ 2009-08-26 17:59 Till Kamppeter
  2009-08-26 18:14 ` Marcel Holtmann
  0 siblings, 1 reply; 12+ messages in thread
From: Till Kamppeter @ 2009-08-26 17:59 UTC (permalink / raw)
  To: linux-bluetooth; +Cc: Mario Limonciello

[-- Attachment #1: Type: text/plain, Size: 1554 bytes --]

Hi,

I am using Bluez 4.48 in Ubuntu Karmic. First thank you for applying my 
patches. The bluetooth backend works perfectly now with CUPS 1.3.x and 
older. On the new CUPS 1.4.x a new problem appeared: The new CUPS does 
device discovery only for a given time frame requested by the client 
(printer setup tool, "lpinfo" command). CUPS's default for 
CUPS-1.3.x-ish requests without timeout specification seems to be 10 
seconds. CUPS startys all backends at once in the beginning (in 
parallel) and kills every backend which remains running at the end of 
the timeout. It accepts output from the backends whenever it occurs not 
only when the backend finishes, so a backend can search for printers 
infinitely long if it outputs every found device immediately. Then all 
printers found during CUPS' timeout are taken into account.

The bluetooth backend o 4.48 asks the Bluetooth daemon for printers and 
collects results for 10 seconds and after that it output them. This 
takes a total of 10.5 sec and so CUPS kills the backend right before it 
answers (at least with the 10-second default timeout), resulting in 
Bluetooth printers never being discovered by CUPS.

I have fixed this now with the attached patch, by making each new 
printer added to the list being output immediately. Note that the list 
structure cannot be removed from cups/main.c as otherwise we would get 
duplicate listings.

Can you please apply this patch to Bluez so that Bluez gets ready for 
the new CUPS 1.4.x generation? Thanks.

    Till

http://www.openprinting.org/



[-- Attachment #2: 10_bluetooth-cups-backend-report-printers-immediately.patch --]
[-- Type: text/x-patch, Size: 2704 bytes --]

diff -Nur -x '*.orig' -x '*~' bluez-4.48/cups/main.c bluez-4.48.new/cups/main.c
--- bluez-4.48/cups/main.c	2009-08-16 20:43:34.000000000 +0200
+++ bluez-4.48.new/cups/main.c	2009-08-26 19:05:31.000000000 +0200
@@ -185,6 +185,27 @@
 	return id;
 }
 
+static void print_printer_details(const char *name, const char *bdaddr, const char *id)
+{
+	char *uri, *escaped;
+
+	escaped = g_strdelimit(g_strdup(name), "\"", '\'');
+	uri = g_strdup_printf("bluetooth://%c%c%c%c%c%c%c%c%c%c%c%c",
+		 bdaddr[0], bdaddr[1],
+		 bdaddr[3], bdaddr[4],
+		 bdaddr[6], bdaddr[7],
+		 bdaddr[9], bdaddr[10],
+		 bdaddr[12], bdaddr[13],
+		 bdaddr[15], bdaddr[16]);
+	printf("direct %s \"%s\" \"%s (Bluetooth)\"", uri, escaped, escaped);
+	if (id != NULL)
+		printf(" \"%s\"\n", id);
+	else
+		printf("\n");
+	g_free(escaped);
+	g_free(uri);
+}
+
 static void add_device_to_list(const char *name, const char *bdaddr, const char *id)
 {
 	struct cups_device *device;
@@ -212,27 +233,7 @@
 	device->id = g_strdup(id);
 
 	device_list = g_slist_prepend(device_list, device);
-}
-
-static void print_printer_details(const char *name, const char *bdaddr, const char *id)
-{
-	char *uri, *escaped;
-
-	escaped = g_strdelimit(g_strdup(name), "\"", '\'');
-	uri = g_strdup_printf("bluetooth://%c%c%c%c%c%c%c%c%c%c%c%c",
-		 bdaddr[0], bdaddr[1],
-		 bdaddr[3], bdaddr[4],
-		 bdaddr[6], bdaddr[7],
-		 bdaddr[9], bdaddr[10],
-		 bdaddr[12], bdaddr[13],
-		 bdaddr[15], bdaddr[16]);
-	printf("direct %s \"%s\" \"%s (Bluetooth)\"", uri, escaped, escaped);
-	if (id != NULL)
-		printf(" \"%s\"\n", id);
-	else
-		printf("\n");
-	g_free(escaped);
-	g_free(uri);
+	print_printer_details(device->name, device->bdaddr, device->id);
 }
 
 static gboolean parse_device_properties(DBusMessageIter *reply_iter, char **name, char **bdaddr)
@@ -384,23 +385,6 @@
 
 static void discovery_completed(void)
 {
-	GSList *l;
-
-	for (l = device_list; l != NULL; l = l->next) {
-		struct cups_device *device = (struct cups_device *) l->data;
-
-		if (device->name == NULL)
-			device->name = g_strdelimit(g_strdup(device->bdaddr), ":", '-');
-		/* Give another try to getting an ID for the device */
-		if (device->id == NULL)
-			remote_device_found(NULL, device->bdaddr, device->name);
-		print_printer_details(device->name, device->bdaddr, device->id);
-		g_free(device->name);
-		g_free(device->bdaddr);
-		g_free(device->id);
-		g_free(device);
-	}
-
 	g_slist_free(device_list);
 	device_list = NULL;
 
@@ -638,6 +622,9 @@
 	/* Make sure status messages are not buffered */
 	setbuf(stderr, NULL);
 
+	/* Make sure output is not buffered */
+	setbuf(stdout, NULL);
+
 	/* Ignore SIGPIPE signals */
 #ifdef HAVE_SIGSET
 	sigset(SIGPIPE, SIG_IGN);

^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2009-08-27  2:35 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-08-10 20:19 PATCHES: Device discovery of the "bluetooth" CUPS backend does not work Till Kamppeter
2009-08-11 10:33 ` Bastien Nocera
2009-08-11 11:19   ` Till Kamppeter
2009-08-11 11:33     ` Bastien Nocera
2009-08-11 12:24       ` Till Kamppeter
2009-08-11 13:12         ` Bastien Nocera
2009-08-11 22:09           ` Marcel Holtmann
2009-08-11 22:14           ` Marcel Holtmann
  -- strict thread matches above, loose matches on Subject: below --
2009-08-26 17:59 Till Kamppeter
2009-08-26 18:14 ` Marcel Holtmann
2009-08-26 19:12   ` Till Kamppeter
2009-08-27  2:35     ` Marcel Holtmann

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