Re: libusb driver question: can't write to endpoint

Alan Stern wrote:

> Does that error string come from usb_strerror()?  My copy of libusb is
> rather old and doesn't seem to include that routine.  It would help to see
> the actual error code returned by usb_interrupt_write().
> 
>> Looking at lsusb, the device has one Configuration with bConfigurationValue
>> 1, and one Interface with bInterfaceNumber 0.
> 
> Then why does your program try to claim interface 1?

Cause I was trying 1 on a whim and forgot to change it back. Doing so
doesn't change the result.

>> Under this interface, it has two endpoints, 0x81, "EP 1 IN", and 0x02, "EP 1
>> OUT",
> 
> Actually that's EP 2 OUT, not that it matters.

Err, yeah.

> Your timeout value of 2 ms seems rather low.  You might want to increase 
> it.

Other values don't make a difference... I started at 10.

> Have you tried setting the usbfs_snoop=1 module parameter for usbcore?  It 
> will dump your program's I/O activity to the system log.

No, I didn't, but that's a good idea. Is there a way to change this
on-the-fly through, say, sysfs? I couldn't rmmod usbcore without -f, and
then re-modprobing it caused and oops (though I am on a relatively old
kernel... 2.6.15.6).

Mar 10 22:15:33 rider kernel: Unable to handle kernel paging request at
virtual address f8854b60
Mar 10 22:15:33 rider kernel:  printing eip:
Mar 10 22:15:33 rider kernel: c0173851
Mar 10 22:15:33 rider kernel: *pde = 37c0e067
Mar 10 22:15:33 rider kernel: *pte = 00000000
Mar 10 22:15:33 rider kernel: Oops: 0000 [#1]
Mar 10 22:15:33 rider kernel: PREEMPT SMP
Mar 10 22:15:33 rider kernel: Modules linked in: iptable_filter ip_tables
rtc thermal fan processor ipv6 dm_mirror eeprom w83627hf hwmon_vid hwmon
i2c_isa nvidia autofs4 sk98lin snd_intel8x0 snd_ac97_codec snd_ac97_bus
snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd skge i2c_i801 soundcore
ide_cd crc32 i2c_core psmouse ohci1394 ieee1394 cdrom snd_page_alloc sd_mod
Mar 10 22:15:33 rider kernel: CPU:    1
Mar 10 22:15:33 rider kernel: EIP:    0060:[<c0173851>]    Tainted: PF     VLI
Mar 10 22:15:33 rider kernel: EFLAGS: 00010246   (2.6.15.6rider-smp)
Mar 10 22:15:33 rider kernel: EIP is at show_vfsmnt+0x78/0x15f
Mar 10 22:15:33 rider kernel: eax: f8854b60   ebx: d48e12c0   ecx: d48e12c0
  edx: 00000189
Mar 10 22:15:33 rider kernel: esi: c17e7b40   edi: d48e12c0   ebp: 00000000
  esp: d3f01f18
Mar 10 22:15:33 rider kernel: ds: 007b   es: 007b   ss: 0068
Mar 10 22:15:33 rider kernel: Process sudo (pid: 4297, threadinfo=d3f00000
task=f7081030)
Mar 10 22:15:33 rider kernel: Stack: d48e12c0 00000020 c02f8c8b c02f8c8b
d48e12c0 c17e7b40 00000176 c0177b3f
Mar 10 22:15:33 rider kernel:        d48e12c0 c17e7b40 d3f01f4c 00000000
d48e12e0 00000009 00000000 00000008
Mar 10 22:15:33 rider kernel:        00000000 d6aa2740 00000400 d3f01fa4
00000000 c0157b9b d6aa2740 b7f52000
Mar 10 22:15:33 rider kernel: Call Trace:
Mar 10 22:15:33 rider kernel:  [<c0177b3f>] seq_read+0x1f3/0x2e4
Mar 10 22:15:33 rider kernel:  [<c0157b9b>] vfs_read+0x9d/0x177
Mar 10 22:15:33 rider kernel:  [<c0157f40>] sys_read+0x4b/0x74
Mar 10 22:15:33 rider kernel:  [<c0102e2d>] syscall_call+0x7/0xb
Mar 10 22:15:33 rider kernel: Code: 08 89 74 24 04 89 3c 24 e8 12 48 00 00
c7 44 24 04 20 00 00 00 89 3c 24 e8 18 4a 00 00 c7 44 24 08 8b 8c 2f c0 8b
46 14 8b 40 20 <8b> 00 89 44 24 04 89 3c 24 e8 d0 46 00 00 8b 56 14 b8 ea 9c 2f


Thanks for your help Alan.

-- 
Phil Dibowitz                             [email protected]
Open Source software and tech docs        Insanity Palace of Metallica
http://www.phildev.net/                   http://www.ipom.com/

"Never write it in C if you can do it in 'awk';
 Never do it in 'awk' if 'sed' can handle it;
 Never use 'sed' when 'tr' can do the job;
 Never invoke 'tr' when 'cat' is sufficient;
 Avoid using 'cat' whenever possible" -- Taylor's Laws of Programming

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFF85+nN5XoxaHnMrsRAlX8AKCIm+DRIb2p+bYfD1vcG2J0GdhIoACggF72
4eWOU0DebSc23TQCuFL+BEU=
=NoLw
-----END PGP SIGNATURE-----