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Based on kernel version 3.13. Page generated on 2014-01-20 21:59 EST.

1	What:           /sys/class/pktcdvd/
2	Date:           Oct. 2006
3	KernelVersion:  2.6.20
4	Contact:        Thomas Maier <balagi@justmail.de>
5	Description:
6	
7	sysfs interface
8	---------------
9	
10	The pktcdvd module (packet writing driver) creates
11	these files in the sysfs:
12	(<devid> is in format  major:minor )
13	
14	/sys/class/pktcdvd/
15	    add            (0200)  Write a block device id (major:minor)
16	                           to create a new pktcdvd device and map
17	                           it to the block device.
18	
19	    remove         (0200)  Write the pktcdvd device id (major:minor)
20	                           to it to remove the pktcdvd device.
21	
22	    device_map     (0444)  Shows the device mapping in format:
23	                             pktcdvd[0-7] <pktdevid> <blkdevid>
24	
25	/sys/class/pktcdvd/pktcdvd[0-7]/
26	    dev                   (0444) Device id
27	    uevent                (0200) To send an uevent.
28	
29	/sys/class/pktcdvd/pktcdvd[0-7]/stat/
30	    packets_started       (0444) Number of started packets.
31	    packets_finished      (0444) Number of finished packets.
32	
33	    kb_written            (0444) kBytes written.
34	    kb_read               (0444) kBytes read.
35	    kb_read_gather        (0444) kBytes read to fill write packets.
36	
37	    reset                 (0200) Write any value to it to reset
38	                                 pktcdvd device statistic values, like
39	                                 bytes read/written.
40	
41	/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/
42	    size                  (0444) Contains the size of the bio write
43	                                 queue.
44	
45	    congestion_off        (0644) If bio write queue size is below
46	                                 this mark, accept new bio requests
47	                                 from the block layer.
48	
49	    congestion_on         (0644) If bio write queue size is higher
50	                                 as this mark, do no longer accept
51	                                 bio write requests from the block
52	                                 layer and wait till the pktcdvd
53	                                 device has processed enough bio's
54	                                 so that bio write queue size is
55	                                 below congestion off mark.
56	                                 A value of <= 0 disables congestion
57	                                 control.
58	
59	
60	Example:
61	--------
62	To use the pktcdvd sysfs interface directly, you can do:
63	
64	# create a new pktcdvd device mapped to /dev/hdc
65	echo "22:0" >/sys/class/pktcdvd/add
66	cat /sys/class/pktcdvd/device_map
67	# assuming device pktcdvd0 was created, look at stat's
68	cat /sys/class/pktcdvd/pktcdvd0/stat/kb_written
69	# print the device id of the mapped block device
70	fgrep pktcdvd0 /sys/class/pktcdvd/device_map
71	# remove device, using pktcdvd0 device id   253:0
72	echo "253:0" >/sys/class/pktcdvd/remove
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