On Thu, 18 Oct 2012, megha dey wrote:
> While trying to copy some file(>400 MB) from PC to device in mass
> storage mode,an I/O error is observed.
>
> From the bus trace, it is observed that vfs_sync() is taking a lot of
> time when handing ALLOW_MEDIUM_REMOVAL.There is a similar problem
> already discussed earlier,although with no concrete conclusion.
>
> http://comments.gmane.org/gmane.linux.usb.general/53896
>
> Even after ~15 secs, we don�t send the Status to PC for the
> ALLOW_MEDIUM_REMOVAL command. Since the vfs_sync command has not
> returned, USB driver is not sending the status.PC is sending the next
> command as it has not received the status for the previous command,and
> this messes up the state diagram.
>
> Issue observed on kernel 3.4 with sandisk 2GB card.
>
> Dees the current mass storage driver (f_mass_storage.c) support such a
> scenario,if not what would be the appropriate solution?
Yuping Luo posted a patch that was almost right:
http://marc.info/?l=linux-usb&m=132024464410783&w=2
See
http://marc.info/?l=linux-usb&m=132032964805789&w=2
for a description of what needed to be added to the patch. The patch
was never fixed up and submitted.
Would you like to update that patch and submit it?
Alan Stern
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