Bug 26909 - USB printer.c read and poll bugs (and patch)
Summary: USB printer.c read and poll bugs (and patch)
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: kernel   
(Show other bugs)
Version: 7.1
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Arjan van de Ven
QA Contact: Brock Organ
URL: http://www.geocrawler.com/lists/3/Sou...
Depends On:
TreeView+ depends on / blocked
Reported: 2001-02-10 02:33 UTC by David Paschal
Modified: 2007-04-18 16:31 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2001-02-13 23:58:40 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description David Paschal 2001-02-10 02:33:25 UTC
From Bugzilla Helper:
User-Agent: Mozilla/4.72 [en] (X11; U; Linux 2.2.18-dsp1 i686)

The biggest problem was that after I successfully read an MLC/1284.4 packet
     on a 7/1/3 interface, every subsequent read would return garbage (but
in the
     exact amount requested).  The problem was that when
     usb_submit_urb(&usblp->readurb) was called in usblp_read(), it failed
to zero
     out usblp->readcount the way it did in usblp_open().

     The second problem was that selecting for a read never triggered when
     had been received, because the check for usblp->bidir in usblp_poll()

I submitted a patch against 2.2.18 to the linux-usb-devel mailing list
(http://www.geocrawler.com/lists/3/SourceForge/2571/0/5123030/).  Looking
at drivers/usb/printer.c in 2.4.x in Fisher, the read bug is partially
fixed, and the poll bug is not fixed.  Hopefully somebody on
linux-usb-devel will ensure that these fixes get incorporated into 2.2.19
and 2.4.2, but I'm submitting this bug report against Fisher so it will get

Reproducible: Always
Steps to Reproduce:
Problem #1 (read):

Connect USB HP OfficeJet G series, K series, or LaserJet 3200.
write(fd,"\0\0\0\8\1\0\0\x20",8); // Send 1284.4 Init packet.
read(fd,buffer,6); // Receive 1284.4 header.
read(fd,buffer+6,3); // Receive data portion of 1284.4 InitReply.
Everything works fine so far.

read(fd,buffer,6); // Receive next 1284.4 header.
This and every subsequent read() returns garbage data in the exact amount
requested, because the readcount variable is not zeroed out when submitting
another readurb.

Problem #2 (poll/select):

fd_set rset;
Never returns even when bulk IN data is available, due to an inverted test
for bidirectionality in usblp_poll().

Comment 1 Glen Foster 2001-02-12 23:14:04 UTC
We (Red Hat) should really try to resolve this before next release.

Comment 2 Arjan van de Ven 2001-02-14 20:45:26 UTC
Thanks for the report. Patch is applied and will be included in the
next kernelbuild in Rawhide.

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