Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750807AbWKBOZn (ORCPT ); Thu, 2 Nov 2006 09:25:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750820AbWKBOZm (ORCPT ); Thu, 2 Nov 2006 09:25:42 -0500 Received: from nf-out-0910.google.com ([64.233.182.189]:10930 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S1750807AbWKBOZm (ORCPT ); Thu, 2 Nov 2006 09:25:42 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:reply-to:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:from; b=cyTiyBLuW0w+V1CoDqqEHADLqOsZkBm52nCSzChVgCii4eBF5N6VxHJTjC3hhOjjfVnMYtUI+WhqXtb9BkYxF0UNPeJwcPHVfOptuO5Ta8QIy9QroGJ6HyyoP/PpjAJvZe89SpHMPcoB3WK2mTy25dgS3lOePDzxtfaknJuakf8= Message-ID: <454A0006.4090505@innova-card.com> Date: Thu, 02 Nov 2006 15:26:14 +0100 Reply-To: Franck User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: Miguel Ojeda CC: Franck , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH update6] drivers: add LCD support References: <20061101014057.454c4f43.maxextreme@gmail.com> <4549B19C.70304@innova-card.com> <653402b90611020544l6e5ded94hc4c932fc1442fcb0@mail.gmail.com> In-Reply-To: <653402b90611020544l6e5ded94hc4c932fc1442fcb0@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit From: Franck Bui-Huu Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 39 Miguel Ojeda wrote: > On 11/2/06, Franck Bui-Huu wrote: >> Hi >> >> Miguel Ojeda Sandonis wrote: >> > Andrew, here it is the coding style fixes. Thanks you. >> > >> > I think the driver is getting ready for freeze until >> > 2.6.20-rc1 (if anyone sees something wrong), so I will >> > try to send just minor fixes like this. >> >> :) >> >> Again, any thoughts on cache aliasing ? >> > > If you have seen something wrong, please tell. What are you thinking about? Sorry for the short/fast question. I'm wondering how does the cache behave here. You have 2 virtual addresses that point to the same location in physical RAM: kernel frame buffer which has a kernel virtual address and the vma you're returning when an application mmap the device. This last address is a user virtual address and is different from the first one. Now let's say that some of the kernel frame buffer data are in the data cache and never be invalidate during this example. The application updates its mmapped frame buffer. During the refresh time, the kernel take a look to its frame buffer to check if something change. Since the 'old' data are still in the data cache and are valid, the kernel will use them instead of the new one set by the application. Franck - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/