Re: usb_bulk_msg timeout w/ rvmalloc

From: Pete Zaitcev (
Date: Tue Oct 09 2001 - 23:51:12 EST

> I have written a driver which, in part, facilitates the usb bulk
> transfer of raw image data. It works fine for small (CIF, QCIF)
> images, but for larger images, kmalloc will not allocate enough
> memory.

How much do you need?
> I copied the rvmalloc code from the cpia2 driver and used it in place
> of kmalloc. The memory allocates fine, but usb_bulk_msg now times out
> when using the pointer to the rvmalloc'd memory. I have been unable to
> find an instance of an existing driver using rvmalloc in conjunction
> with usb_bulk_msg.

The best thing would be to use pipelined transfer with
several URBs, I think. If that is too difficult for you,
try to use __get_free_pages(), but mind that even if free
RAM is available, kernel may not be able to fulfill your
request. Check response codes carefuly.

-- Pete
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This archive was generated by hypermail 2b29 : Mon Oct 15 2001 - 21:00:29 EST