From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: buffer producer/consumer sync Date: Tue, 9 Mar 2004 10:43:46 +0000 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <20040309104346.C1987@flint.arm.linux.org.uk> References: <20040309101827.A1987@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: ; from perex@suse.cz on Tue, Mar 09, 2004 at 11:23:45AM +0100 Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Jaroslav Kysela Cc: "Gupta, Kshitij" , alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org On Tue, Mar 09, 2004 at 11:23:45AM +0100, Jaroslav Kysela wrote: > Ok, I though that vma->vm_page_prot fix is sufficient for this purpose but > appearently not. Unfortunately not - as the code currently stands, not only are userspace mappings cached, but also kernel mappings of the same pages. Unfortunately changing userspace mappings to be uncached only solves half the problem. We also need to solve the kernel space problem as well. However, this needs to be done in an architecture specific way, which in turn means sorting out something which architecture people are happy with. Then there's the issue about the abuse of virt_to_page() taking a mapped virtual address (ie from pci_alloc_consistent or dma_alloc_coherent) rather than a direct-mapped virtual address (alloc_pages / kmalloc). -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click