From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 10 Oct 2001 00:50:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 10 Oct 2001 00:50:47 -0400 Received: from nat-pool-meridian.redhat.com ([199.183.24.200]:36711 "EHLO devserv.devel.redhat.com") by vger.kernel.org with ESMTP id ; Wed, 10 Oct 2001 00:50:40 -0400 Date: Wed, 10 Oct 2001 00:51:12 -0400 From: Pete Zaitcev Message-Id: <200110100451.f9A4pCW10769@devserv.devel.redhat.com> To: paul.thacker@st.com, linux-kernel@vger.kernel.org Subject: Re: usb_bulk_msg timeout w/ rvmalloc In-Reply-To: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > 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