Re: [Libusb-devel] libusb lsusb 0.72-4 question/bug?

[John S. <jo...@st...>]

>>>>> "Robert" == Robert Heller <he...@de...> writes:

Robert> At Sat, 12 Aug 2006 15:38:35 -0400 "Charles Lepple" <cl...@gm...> wrote:
>> 
>> On 8/12/06, John Stoffel <jo...@st...> wrote:
>> > - I was having a problem where I could do 'lsusb' and see the device,
>> >   but I found that if I pulled one of the two cards it would sometimes
>> >   not notice properly when the card was replugged and I would get a
>> >   bunch of errors like:
>> >
>> >       sdf : READ CAPACITY failed.
>> >       sdf : status=0, message=00, host=1, driver=00
>> >       sdf : sense not available.
>> >        4:0:0:3: rejecting I/O to dead device
>> >       sdf: Write Protect is off
>> >       sdf: Mode Sense: 00 00 00 00
>> >       sdf: assuming drive cache: write through
>> >        4:0:0:2: rejecting I/O to dead device
>> >        4:0:0:2: rejecting I/O to dead device
>> >        sdf:<3> 4:0:0:2: rejecting I/O to dead device
>> >        unable to read partition table
>> >        4:0:0:2: rejecting I/O to dead device
>> >        4:0:0:3: rejecting I/O to dead device
>> 
>> Also not a libusb issue, but you probably won't get those messages if
>> you do something like 'eject /dev/sdf' before pulling the media from
>> the reader.
>> 
>> I don't know the specifics, but it probably flushes the buffers and
>> tells the kernel not to try reading from that device until it sees
>> another card.

Robert> umount does this, not eject.  Eject just sends the 'Eject
Robert> Media' message to the device.  Only works for devices that can
Robert> be told such messages, which includes most (all?) CD/DVD-ROMS,
Robert> and some other devices, like Zip drives.  Does not work for
Robert> typical PC style floppy drives (but does for Mac and Sun type
Robert> floppies (which lack a manual eject button)). Obviously not
Robert> for USB memory sticks.  May or may not work for a flash card
Robert> reader (aren't most of these just a matter manually pulling
Robert> the media out?).

I never mounted any of the media in the reader.  I'm just working on
getting it so that I can put media into the unit, hit the button on
the side, and then have Linux re-scan the device looking for
new/updated media entries.  Not sure how well it's going to work out,
but hey, it's a fun side project. 

Robert> One should do a umount /dev/sdf<mumble> before removing the
Robert> media.  Pulling media (of *any* sort -- floppies, CD/DVD-ROMs,
Robert> Zip Carts, or flash cards/sticks) without unmounting it causes
Robert> the kernel to be most unhappy, often to the point a requiring
Robert> a reboot to fix.

I never said I was mounting the media.  

Currently, with my single CF card reader, I just pull the entire
reader from the USB bus when I want to swap cards.  With the ImageMate
12-in-1 card reader, it's more of a pain, especially since I might
have multiple cards mounted, but only want to pull one of them.

I probably need to take this over to the linux USB mailing list
instead.

Thanks,
John