Hi All,
Quick intro, I'm a Linux enthousiast / developer. Some time ago I've tried to
use the cardreader of my HP PSC 1350 with an sd-card and it didn't work, the
result was:
Jul 14 21:39:38 shalem kernel: drivers/usb/class/usblp.c: usblp0: USB
Bidirectional printer dev 3 if 1 alt 0 proto 2 vid 0x03F0 pid 0x3B11
Jul 14 21:39:38 shalem kernel: scsi5 : SCSI emulation for USB Mass Storage
devices
Jul 14 21:39:43 shalem kernel: scsi 5:0:0:0: Direct-Access HP
1.00 PQ: 0 ANSI: 2
Jul 14 21:39:43 shalem kernel: sd 5:0:0:0: [sdb] Attached SCSI removable disk
Jul 14 21:39:43 shalem kernel: sd 5:0:0:0: Attached scsi generic sg2 type 0
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] 1999872 512-byte hardware
sectors (1024 MB)
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] Write Protect is off
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] Assuming drive cache: write
through
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] 1999872 512-byte hardware
sectors (1024 MB)
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] Write Protect is off
Jul 14 21:40:31 shalem kernel: sd 5:0:0:0: [sdb] Assuming drive cache: write
through
Jul 14 21:40:31 shalem kernel: sdb: sdb1
Jul 14 21:40:32 shalem kernel: sd 5:0:0:0: [sdb] Result: hostbyte=DID_OK
driverbyte=DRIVER_SENSE,SUGGEST_OK
Jul 14 21:40:32 shalem kernel: sd 5:0:0:0: [sdb] Sense Key : Medium Error
[current]
Jul 14 21:40:32 shalem kernel: sd 5:0:0:0: [sdb] Add. Sense: Read error - loss
of streaming
Jul 14 21:40:32 shalem kernel: end_request: I/O error, dev sdb, sector 1999864
I noticed that the error were caused really close to the end of the sdcard, so
I started experimenting, this resulted in me writing the following to the
usb-storage mailinglist some time ago:
---
So after 3 long evenings of debugging, I finally have my cardreader working
"properly".
At first I tried and succeeded with US_FL_FIX_CAPACITY, that worked but gave me
warnings that the partition was larger then the device, and read access beyond
the end of device errors. But it worked now!
Further debugging has lead me to the following conclusion (with a few not
suitable for submitting usb-storage mods to proof it, proof as in it works).
The HP PSC 1350 reader will "crash" and from that moment on no longer
communicate in any sane way, if you try to read the last sector of an sdcard*
in a read that is more then 1 sector, so trying to read 8 sectors starting at
sector capicity-8 will crash it, as will reading 2 sectors starting at sector
capicity-2, however reading the last sector in a one 1 sector read will
succeed! (* xdcards seem to be fine).
I haven't tried if it will crash on larger then 1 sector writes which include
the last sector too, I immediately added code to not do that in both the read
and write paths. I have tested reading and writing the end of the disk with
this kludge in and it works.
As said I currently have an "really ugly" (tm) patch which modifies READ_10 and
WRITE_10 commands in the usb-storage driver. Before I write a "proper" patch I
have some questions:
1) currently I have decided to add quirk code for this to the usb-storage
driver, as I don't want to polute the generic scsi code with this, but maybe
it would be better to add a quirk for this to the scsi layer?
2) What on earth should I name the flag for this?
3) Currently I just shorten the read / write by one sector. The scsi layer then
notices the 1 sector to short read/write and sends a new command for the
last sector. This works well, but is it ok to depend on the scsi layer
behaving this way?
4) Should I be checking for other READ_X and WRITE_x commands too?
---
After some discussion I wrote a patch to the Linux kernel fixing this:
http://people.atrpms.net/~hdegoede/usb-storage-psc1350-v2.patch
Up till now however this patch has not been accepted yet, because its a bit
ugly and the usb-storage maintainers would first like to see it being tested
successfully be others.
I've found several forum posts on the internet with people having the same
problem, but sofar I haven't found anyone willing to test my patch and confirm
it fixes things for them too. Which brings me to this list.
Can you please:
1) Try the card reader of a HP PSC 1350 with Fedora 7 or another distro with
kernel 2.6.22 (the kernel version might be important) and an sdcard and see
if you get similar errors as I did?
2) Try the card reader of other HP printers with about the same age as the HP
PSC 1350 with kernel 2.6.22 and an sdcard and see if you get similar errors
as I did?
3) Try my patch and see if it fixes things for you. For easy testing I've made
available a stand alone compilable patched usb-storage module here:
http://people.atrpms.net/~hdegoede/usb-storage.tar.gz
Usage instructions.
<install kernel-devel, or your distro's equivalent>
<untar>
cd usb-storage
make
<unmount and unplug / turnoff any usb mass storage devices>
sudo rmmod usb-storage
insmod usb-storage.ko
<turn on printer and plugin sd-card>
Many many Thanks!
Regards,
Hans
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
HPLIP-Devel mailing list
HPLIP-Devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/hplip-devel
