From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.free-electrons.com ([88.190.12.23]) by canuck.infradead.org with esmtp (Exim 4.72 #1 (Red Hat Linux)) id 1Pa8RU-0002zD-Eg for barebox@lists.infradead.org; Tue, 04 Jan 2011 15:05:00 +0000 Message-ID: <4D23370A.6040203@free-electrons.com> Date: Tue, 04 Jan 2011 16:04:42 +0100 From: Gregory CLEMENT MIME-Version: 1.0 References: <4D233027.9030701@free-electrons.com> <201101041546.53030.jbe@pengutronix.de> In-Reply-To: <201101041546.53030.jbe@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 1/4] ARM STM/i.MX: Allocate memory for framebuffer during probe To: Juergen Beisert Cc: barebox@lists.infradead.org On 01/04/2011 03:46 PM, Juergen Beisert wrote: > Gregory CLEMENT wrote: >> With current code when the framebuffer is register, screen_base is not >> set yet. So when we want to access framebuffer from mmap we get a >> pointer to 0x0 instead of getting the pointer to the framebuffer >> address. This patch fix this bug by allocating memory for framebuffer >> during probe just before registering framebuffer driver. > > Are you sure? See below It was the value I get at runtime at least. > >> Signed-off-by: Gregory CLEMENT [...] > > This probe function sets up the default mode. And register_framebuffer() > itself calls stmfb_activate_var() which calls stmfb_memory_mmgt(). So, when > the call to register_framebuffer() returns the 'screen_base' should no longer > be NULL. But in register_framebuffer first map_base get its value from screen_base and it is only after that fb_activate_var is called. And the problem is that mmap will not get screen_base but map_base and this one is set too early. Extract from register_framebuffer() in fb.c: info->cdev.dev->map_base = (unsigned long)info->screen_base; map_base get its value here ------^ info->cdev.dev->size = info->cdev.size; dev = &info->dev; dev->priv = info; dev->id = id; sprintf(dev->name, "fb"); register_device(&info->dev); dev_add_param(dev, "enable", fb_enable_set, NULL, 0); dev_set_param(dev, "enable", "0"); if (info->num_modes && (info->mode_list != NULL) && (info->fbops->fb_activate_var != NULL)) { dev_add_param(dev, "mode_name", fb_setup_mode, NULL, 0); dev_set_param(dev, "mode_name", info->mode_list[0].name); fb_activate_var is called here ------------------------^ This code is new for me, maybe I missed something. > > jbe > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox