From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wyyuc-0005qh-Tz for barebox@lists.infradead.org; Mon, 23 Jun 2014 07:43:35 +0000 Date: Mon, 23 Jun 2014 09:43:08 +0200 From: Sascha Hauer Message-ID: <20140623074308.GU15686@pengutronix.de> References: <20140618195849.GL15686@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: i.MX6 frame buffer inside barebox? To: Holger Schurig Cc: "barebox@lists.infradead.org" On Mon, Jun 23, 2014 at 09:25:02AM +0200, Holger Schurig wrote: > Whaaa, it never occured to me that I have to enable the framebuffer as > well... thanks, now it works. barebox has nothing useful to show on the screen until some splash command has been executed, so it's better to leave the display diabled to avoid unnecessary flickering. > > As for simplefb, I removed that. I thought that this sets up a > framebuffer in the bootloader, which when Linux' framebuffer driver > takes over, without reprogramm or screen flicker. However, it seems > that this only works with specific framebuffer patterns, e.g. some 16 > and 32 bit special rgb formats. I don't really get the need for that, > because the bootloader already has programmed the graphics device > correctly, the Linux driver could just re-use that information, so I > don't really see a need why the framebuffer organization has to be > present in the device tree in yet-another-format (tm). The simplefb driver in the kernel is completely hardware agnostic. It's just a way for the firmware to give an already initialized framebuffer to Linux and to run Linux graphics without having a framebuffer driver under Linux. The IPU driver cannot take over an already initialized framebuffer, instead it will reset and reconfigure the IPU during initialization. I'm not sure which direction this passing-a-framebuffer-from-bootloader-to-linux will take, but the current situation is less than satisfying. My preferred solution is to be fast enough in the bootloader and show a splash screen under Linux only. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox