From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Gatliff Subject: Re: flicker free booting Date: Fri, 31 Jul 2009 14:51:49 -0500 Message-ID: <4A734B55.7030205@billgatliff.com> References: <20090602172941.GL3095@hansolo.jdub.homelinux.org> <1243964577.4229.49.camel@mulgrave.int.hansenpartnership.com> <20090602175244.GB10973@cuplxvomd02.corp.sa.net> <20090602185143.GA8655@zod.rchland.ibm.com> <4A257DF0.6040607@am.sony.com> <1243975064.6342.10.camel@mulgrave.site> <20090602213452.GK32630@pengutronix.de> <20090603033535.GA24291@kroah.com> <20090731152617.GW29245@pengutronix.de> <20090731155352.GA29245@pengutronix.de> <20090731180309.GA17314@cuplxvomd02.corp.sa.net> <4A733C07.3050002@billgatliff.com> <4A734A95.6060703@am.sony.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A734A95.6060703@am.sony.com> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Tim Bird Cc: David VomLehn , Robert Schwebel , linux-embedded@vger.kernel.org, Juergen Beisert , Sascha Hauer , Wolfram Sang Tim Bird wrote: > Bill Gatliff wrote: > >> Those fractions-of-seconds boot times are beyond the reach of the 200 >> MHz-class ARM9 processors and similar, where it takes two or three >> seconds just to load and uncompress the kernel from NOR or NAND flash. >> > While I don't disagree from a practical standpoint - at Sony > using XIP we have been able to finish kernel boot on a 192 MHZ ARM9 > in 186 milliseconds. In the lab, anyway? > Yea, that's an upside of XIP: no uncompression stage. :) I wonder, though, if the bandwidth limitations of NOR flash make the system slower overall? I guess the bootloader could copy an uncompressed image from flash into RAM, and then XIP it from there to get the best of both worlds, if you could stand the time hit of the memcpy... b.g. -- Bill Gatliff bgat@billgatliff.com