Messages in this thread Patch in this message | | | Date | Sun, 15 Feb 2004 13:55:32 -0800 | From | Andy Lutomirski <> | Subject | [BUG] usblp_write spins forever after an error |
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I recently cancelled a print job with the printer's cancel function, and the CUPS backend got stuck in usblp_write (using 100% CPU and not responding to signals).
The printer is a Kyocera Mita FS-1900 (which has some other problems with the linux USB code: usblp_check_status often times out, even though the printer is bidirectional -- but that's a whole different issue).
It looks like the problem is that the write failed, so wcomplete got set to 1 and the status is nonzero. This case appears to be mishandled in usblp.c:
while (writecount < count) { if (!usblp->wcomplete) { [... not reaching this code] }
down (&usblp->sem); if (!usblp->present) { up (&usblp->sem); return -ENODEV; } if (usblp->writeurb->status != 0) {
[ check status? ]
schedule (); continue; <-- problem }
After the write fails, the current code keeps checking the same status, and never checks for signals or fails. I'm not sure what the right fix is, but it might be something like this:
--- ./usblp.c.orig 2004-02-15 06:27:29.176169752 -0800 +++ ./usblp.c 2004-02-15 06:29:40.137260640 -0800 @@ -645,13 +645,11 @@ err = usblp->writeurb->status; } else err = usblp_check_status(usblp, err); - up (&usblp->sem);
- /* if the fault was due to disconnect, let khubd's - * call to usblp_disconnect() grab usblp->sem ... - */ - schedule (); - continue; + writecount += usblp->writeurb->transfer_buffer_length; + up (&usblp->sem); + count = writecount ? writecount : err; + break; }
writecount += usblp->writeurb->transfer_buffer_length;
--Andy
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