From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.ukfsn.org ([77.75.108.3]:40542 "EHLO mail.ukfsn.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032236Ab2CPAZo (ORCPT ); Thu, 15 Mar 2012 20:25:44 -0400 Message-ID: <4F628886.3050009@ukfsn.org> Date: Fri, 16 Mar 2012 00:25:42 +0000 From: Andy Furniss MIME-Version: 1.0 To: Gianluca Gennari CC: linux-media@vger.kernel.org, mchehab@redhat.com, dheitmueller@kernellabs.com Subject: Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers References: <1329155962-22896-1-git-send-email-gennarone@gmail.com> In-Reply-To: <1329155962-22896-1-git-send-email-gennarone@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Gianluca Gennari wrote: > (was: Re: PCTV 290e page allocation failure) > > On MIPS/ARM set-top-boxes, as well as old x86 PCs, memory allocation failures > in the em28xx driver are common, due to memory fragmentation over time, that > makes impossible to allocate large chunks of coherent memory. > A typical system with 256/512 MB of RAM fails after just 1 day of uptime (see > the old thread for detailed reports and crashlogs). > > In fact, the em28xx driver allocates memory for USB isoc transfers at runtime, > as opposite to the dvb-usb drivers that allocates the USB buffers when the > device is initialized, and frees them when the device is disconnected. > > Moreover, in digital mode the USB isoc transfer buffers are freed, allocated > and cleared every time the user selects a new channel, wasting time and > resources. Does this patch have a chance of getting in? I am still having to flush caches before use. If you want more testing I can give it a go. I didn't earlier as I didn't have a git to apply it to and thought it was going to get in anyway.