linux-toradex.git/drivers/usb/class/usblp.c, branch v2.6.30-rc8

usblp: continuously poll for status

2009-03-24T23:20:26+00:00

The usblp in 2.6.18 polled for status regardless if we actually needed it.
At some point I dropped it, to save the batteries if nothing else.
As it turned out, printers exist (e.g. Canon BJC-3000) that need prodding
this way or else they stop. This patch restores the old behaviour.
If you want to save battery, don't leave jobs in the print queue.

I tested this on my printers by printing and examining usbmon traces
to make sure status is being requested and printers continue to print.
Tuomas Jäntti verified the fix on BJC-3000.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

USB: usblp.c: add USBLP_QUIRK_BIDIR to Brother HL-1440

2009-01-28T00:15:36+00:00

My Brother HL-1440 would print one document before CUPS would stop
printing with the error "Printer not connected; will retry in 30
seconds...". I traced this down to the CUPS usb backend getting an EIO
out of usblp on the IOCNR_GET_DEVICE_ID IOCTL. Adding the
USBLP_QUIRK_BIDIR fixes the problem but is it the right solution?

output from strace /usr/lib/cups/backend/usb after printing a document
(Note: SNDCTL_DSP_SYNC == IOCNR_GET_DEVICE_ID):

before patch

open("/dev/usb/lp0", O_RDWR|O_EXCL)     = 3
ioctl(3, SNDCTL_DSP_SYNC, 0x7fff2478cef0) = -1 EIO (Input/output error)

after patch

open("/dev/usb/lp0", O_RDWR|O_EXCL)     = 3
ioctl(3, SNDCTL_DSP_SYNC, 0x7fffb8d474c0) = 0

Possibly related bug: https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/35638

Signed-off-by: Brandon Philips 
Signed-off-by: Greg Kroah-Hartman

USB: remove err() macro from usb class drivers

2008-10-17T21:41:10+00:00

USB should not be having it's own printk macros, so remove err() and
use the system-wide standard of dev_err() wherever possible.  In the
few places that will not work out, use a basic printk().

Signed-off-by: Greg Kroah-Hartman

drivers/usb/class/usblp.c: adjust error handling code

2008-10-17T21:40:51+00:00

In this code, it is possible to tell statically whether usblp will be NULL
in the error handling code.

Oliver Neukum suggested to make a goto to the final return rather than 
return directly.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// 
@@
identifier f,err,l,l1;
type T;
expression x,E;
statement S;
@@

x = NULL
... when != goto l1;
* x = f(...)
... when != x
err = E;
goto l;
...
* if (x != NULL)
  S
return err;
// 

Signed-off-by: Julia Lawall 
Cc: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

USB: fix pm counter leak in usblp

2008-02-21T23:38:48+00:00

if you fail in open() you must decrement the pm counter again.

Signed-off-by: Oliver Neukum 
Cc: stable 
Signed-off-by: Pete Zaitcev

usblp: Fix a double kfree

2007-10-12T21:55:15+00:00

If submit fails, slab hits a BUG() because of a double kfree.
The today's lesson is, you cannot just slap USB_FREE_BUFFER on code
without adjusting the error paths.

The patch is made bigger by opportunistic refactoring.

Signed-Off-By: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

usblp: Cosmetics

2007-10-12T21:55:14+00:00

This is a small bunch of cosmetic fixes:
 - Timeout is not a write timeout anymore, rename
 - Condition in poll was confusingly backwards, invert and simplify
 - The comment log gave a wrong impression of version 0.13, terminate it.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

usblp: mutex in usblp_check_status

2007-10-12T21:55:14+00:00

Add a mutex to protect the ->statusbuf. Not really an issue, because CUPS
is single-threaded when it talks to the printer, but I feel safer this way.
This should be deadlock-free, but I kept this as a separate patch in case
someone ends running a git bisect.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

usblp: Make use of URB_FREE_BUFFER

2007-10-12T21:54:58+00:00

Employ the new API URB_FREE_BUFFER that we've got. There was talk of a combined
constructor for this case, but apparently it's not happening, so just set the
flag explicitly for now.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

usblp: Implement the ENOSPC convention

2007-10-12T21:54:58+00:00

This patch implements a mode when a printer returns ENOSPC when it runs
out of paper. The default remains the same as before. An application which
wishes to use this function has to enable it explicitly with an ioctl
LPABORT.

This is done on a request by our (Fedora) CUPS guy, Tim Waugh. The API is
similar enough to the lp0's one that CUPS works with both (but see below),
but it's has some differences.

Most importantly, the abort mode is persistent in case of lp0: once tunelp
was run your cat fill blow up until you reboot or run tunelp again. For
usblp, I made it so the abort mode is only in effect as long as device
is open. This way you can mix and match CUPS and cat(1) freely and nothing
bad happens even if you run out of paper. It is also safer in the face
of any unexpected crashes.

It has to be noted that mixing LPABORT and O_NONBLOCK is not advised.
It probably does not do what you want: instead of returning -ENOSPC
it will always return -EAGAIN (because it would otherwise block while
waiting for the paper). Applications which use O_NONBLOCK should continue
to use LPGETSTATUS like before.

Finally, CUPS actually requires patching to take full advantage of this.
It has several components; those which invoke LPABORT work, but some of
them need the ioctl added. This is completely compatible, you can mix
old CUPS and new kernels or vice versa.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman