From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gupta, Ramesh" Subject: RE: dma_alloc_coherent fragmentation Date: Wed, 22 Apr 2009 14:44:59 +0530 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:43165 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755301AbZDVJQi convert rfc822-to-8bit (ORCPT ); Wed, 22 Apr 2009 05:16:38 -0400 In-Reply-To: Content-Language: en-US Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: pramod gurav , "Menon, Nishanth" Cc: "linux-omap@vger.kernel.org" Hi Pramod, > -----Original Message----- > From: linux-omap-owner@vger.kernel.org > [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of pramod gurav > Sent: Wednesday, April 22, 2009 1:17 PM > To: Menon, Nishanth > Cc: linux-omap@vger.kernel.org > Subject: Re: dma_alloc_coherent fragmentation > > Hi Nishant, > I am facing the same problem to allocate a chunk of 4MB on omap3evm > using dma_alloc_coherent. I used the test driver mentioned here > http://www.mail-archive.com/linux-omap@vger.kernel.org/msg11074.html > > I applied the patch for > ioremap(24f11ec001920f1cfaeeed8e8b55725d900bbb56) suggested by > Russell, but stiill seeing the error saying > > coherent allocation too big (requested 0x400000 mask 0xffffffff) > alloc[0] - virt=0x00000000 phy=0xFFFFFFFF size=0x00400000 > Allocation failed idx=0 > insmod: cannot insert `dummy.ko': Cannot allocate memory (-1): Cannot > allocate memory > > I changed the GFP_KERNEL to GFP_TEMPORARY and also to (GFP_KERNEL | > __GFP_RECLAIMABLE), but failed to insmod the module. > I am working on linux-omap 2.6.28 kernel. Even I could not allocate > memory size greater than 1MB. > Has this been fixed? Are there any patches to fix this issue? > What is the value for 'CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE' (default is 2 in omap_3430sdp_defconfig), Can you please try increasing to 8? Regards Ramesh Gupta G