[gphoto-bugs] [ gphoto-Bugs-1429301 ] PTP error downloading certain sized files on iRiver T series

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Bugs item #1429301, was opened at 2006-02-10 13:57
Message generated for change (Comment added) made by bengreenfeld
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Ben Greenfeld (bengreenfeld)
Assigned to: Marcus Meissner (marcusmeissner)
Summary: PTP error downloading certain sized files on iRiver T series

Initial Comment:
I haven't narrowed down the problem much yet, but bad 
things happen when the file size + 12 byte header is 
divisible by 512.

Tested with 500, 1012, and 2036 byte files. 4084 byte 
file worked fine. Haven't tried >4k yet. Others had 
this result:

--
0.403442 gphoto2-port(2): Reading 4096=0x1000 bytes 
from port...
0.425535 gphoto2-port(2): Could only read 524 out of 
4096 byte(s)
0.425588 gphoto2-port(3): Hexdump of 524 = 0x20c bytes 
follows:
0000  00 02 00 00 02 00 09 10-49 00 00 00 78 78 78 
78  ........I...xxxx
0010  78 78 78 78 78 78 78 78-78 78 78 78 78 78 78 78  
xxxxxxxxxxxxxxxx
0020  78 78 78 78 78 78 78 78-78 78 78 78 78 78 78 78  
xxxxxxxxxxxxxxxx
...
01e0  78 78 78 78 78 78 78 78-78 78 78 78 78 78 78 78  
xxxxxxxxxxxxxxxx
01f0  78 78 78 78 78 78 78 78-78 78 78 78 78 78 78 0a  
xxxxxxxxxxxxxxx.
0200  0c 00 00 00 03 00 01 20-49 00 00 
00              ....... I...

0.425680 gphoto2-port(2): Reading 4096=0x1000 bytes 
from port...
8.426389 PTP2/library.c(2): PTP: gp_port_* function 
returned 0xffffffde          -34
8.426498 context(0): PTP I/O error
--

Reads 524 bytes when it should read 512, and ends up 
getting the followup packet too. File is not saved to 
disk as a result.

Also, interesting that there is no extra byte for 
a "short write" after the file data has been sent.

----------------------------------------------------------------------

>Comment By: Ben Greenfeld (bengreenfeld)
Date: 2006-02-13 14:35

Message:
Logged In: YES 
user_id=1425290

linux-2.6.12-gentoo-r10
libusb: 0.1.10a
(and iRiver T10 Firmware 1.60)

This issue doesn't come up if 
PTP_USB_BULK_HS_MAX_PACKET_LEN is switched back to 512, as 
expected. But it still doesn't send the short write at the 
end.

Headaches on this end too...

----------------------------------------------------------------------

Comment By: Marcus Meissner (marcusmeissner)
Date: 2006-02-13 07:27

Message:
Logged In: YES 
user_id=48092

yeah, this specific MTP protocol particularity is causing 
me headaches :( 
 
for reference, which kernel and libusb do you use? 

----------------------------------------------------------------------

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