Bug 4563
| Summary: | read from usblp don't work | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Jean-Jacques Sarton (jj.sarton) |
| Component: | USB | Assignee: | Greg Kroah-Hartman (greg) |
| Status: | REJECTED UNREPRODUCIBLE | ||
| Severity: | high | CC: | jj.sarton |
| Priority: | P2 | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.9 2.6.10 2.6.11 | Subsystem: | |
| Regression: | --- | Bisected commit-id: | |
| Bug Depends on: | |||
| Bug Blocks: | 5089 | ||
What kernel did the read() call block for you? We need more information here. Does the driver not work properly? I try to read data fronn the printer and I expect that if the
printer have nothing to send to my application, the read call
block.
On the 2.4 kernel serie the call was blocking, this is no more
the the fact with the 2.6 kernels.
In my opinion the driver dont work properl. If an application issue
an open("/dev/usb/lp0", O_RDWR); as consecutive read has to block
unless an appropriate system call make the read call non blocking.
What for data do you need ?
Sorry, but that's not the way the driver works anymore. Not much I can do about it... Therefore the parallel printer port and the usb printer port will work differently, this is not a nice feature. Ok, I just tested this with my printer, and 2.6.13-rc6, and it blocks if no data is to be read from the printer. So yes, it does work like 2.4 this way. Perhaps your printer really is responding with data? |
Distribution: Fedora Core 3 Hardware Environment: EPSON Printer on Notebook Software Environment: Kernel 2.6.9, 2.6.10. 2.6.11, readin of Printer informations via the status monitor mtink. Problem Description: The read() call is no more blockink as for older kernel. Furthermore read may return characters which are not send bay the printer. The poll call don't block for the POLLIN event query. Steps to reproduce: cat /dev/usb/lp0 is suffincientz in order to see that the read call is not blocking. Attaching an EPSON printer via USB and querying datas fail (http;// xwtools.automatix.de)