From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Re: [RESEND][PATCH] sm501fb: clear framebuffer memory and palette Date: Wed, 30 Jan 2008 11:14:41 +0000 Message-ID: <20080130111441.GB7089@fluff.org.uk> References: <20080121105925.12446.36815.sendpatchset@clockwork.opensource.se> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1JKAu1-0004DV-H9 for linux-fbdev-devel@lists.sourceforge.net; Wed, 30 Jan 2008 03:14:49 -0800 Received: from 87-194-8-8.bethere.co.uk ([87.194.8.8] helo=kira.home.fluff.org) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1JKAtz-0000Nf-RG for linux-fbdev-devel@lists.sourceforge.net; Wed, 30 Jan 2008 03:14:49 -0800 Received: from ben by kira.home.fluff.org with local (Exim 4.68) (envelope-from ) id 1JKAtt-0006rB-4V for linux-fbdev-devel@lists.sourceforge.net; Wed, 30 Jan 2008 11:14:41 +0000 Content-Disposition: inline In-Reply-To: <20080121105925.12446.36815.sendpatchset@clockwork.opensource.se> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: linux-fbdev-devel@lists.sourceforge.net On Mon, Jan 21, 2008 at 07:59:25PM +0900, Magnus Damm wrote: > sm501fb: clear framebuffer memory and palette > > Avoid displaying garbage on unused framebuffers. For most users a single > framebuffer is used together with fbcon. sm501fb supports two framebuffers > where one often is assigned to fbcon and the other one is left unused during > the boot. > > The problem here is that framebuffers not in use by fbcon happen to display > garbage. This can easily be solved by making sure that framebuffer memory and > palette ram are cleared. > > The problem can be observed by using looking at the panel output (fb1) > after booting the kernel with fbcon on crt (fb0). This is the default > configuration. It's also possible to watch the garbage on the crt framebuffer > by passing "fbcon=map:1" on the kernel cmdline. This will assign fbcon to > the panel (fb1) and leave the crt (fb0) unused. Can you please add a no-clear-on-init flag incase people do not want their framebuffers cleared. > Signed-off-by: Magnus Damm > --- > > This is the same patch that was sent to linux-fbdev-devel on 20071228. > > drivers/video/sm501fb.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > --- 0002/drivers/video/sm501fb.c > +++ work/drivers/video/sm501fb.c 2007-12-27 13:24:20.000000000 +0900 > @@ -1264,6 +1264,7 @@ static int sm501fb_start(struct sm501fb_ > { > struct resource *res; > struct device *dev; > + int k; > int ret; > > info->dev = dev = &pdev->dev; > @@ -1325,6 +1326,13 @@ static int sm501fb_start(struct sm501fb_ > > info->fbmem_len = (res->end - res->start)+1; > > + /* clear framebuffer memory - avoids garbage data on unused fb */ > + memset(info->fbmem, 0, info->fbmem_len); > + > + /* clear palette ram - undefined at power on */ > + for (k = 0; k < (256 * 3); k++) > + writel(0, info->regs + SM501_DC_PANEL_PALETTE + (k * 4)); > + > /* enable display controller */ > sm501_unit_power(dev->parent, SM501_GATE_DISPLAY, 1); > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Linux-fbdev-devel mailing list > Linux-fbdev-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel -- Ben (ben@fluff.org, http://www.fluff.org/) 'a smiley only costs 4 bytes' ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/