[Gta04-owner] NAND behavior while flashing qtmoko

[Andreas Kemnade]

Hi,

On Mon, 26 Mar 2012 11:14:17 +0200
"Dr. H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> 
> Am 26.03.2012 um 10:53 schrieb Andreas Kemnade:
> 
> > Hi,
> > 
> > On Mon, 26 Mar 2012 09:20:01 +0200
> > Radek Polak <psonek2 at seznam.cz> wrote:
> > 
> >> On Sunday 25 March 2012 17:12:21 Michele Brocco wrote:
> >> 
> >>> just want to report some experiences while flashing qtmoko to NAND:
> >>> 
> >>> - first, why has the qtmoko kernel a hardcoded path for the rootfs?
> >>> Why doesn't it get the parameters from u-boot?
> >> 
> >> It's quite hard to troubleshoot problems if everyone used different boot 
> >> params. I am using the same boot cmdline as Neil Brown's kernel. I am not 
> >> kernel developer and i believe that he has got them right.
> >> 
> > But why are you not using
> > CONFIG_CMDLINE_EXTEND=y
> > 
> > Then you can choose to provide only the rootfs via uboot and not
> > other complicated stuff. I do not know why it makes troubleshoot
> > problems significant harder if the user can choose the rootfs partition.
> > On desktops that does not cause problems. On GTA02 you could choose
> > your rootfs from the bootloader. 
> > But I also doubt that the commandline is a good place for so many configurations
> > for regular use.
> 
> Yes, there should be only two configs choosen from the bootloader:
> * rootfs location (but not rootfs type - if possible)
> * display (so that we may boot on TVout)
> 
> Then it is not necessary to change anything in u-boot (or bootargs)
> for different distros.
> 
BTW: CONFIG_CMDLINE_EXTEND (which merges the bootloaders command line with the one
integrated into the kernel) is really the option I use on my GTA04.

> > With that setting we can start about thinking about a mechanism to
> > configure the boot loader from distro scripts.
> 
> That is something I would prefer to avoid. The reason is that you
> can break so much very easily and then you need access to the
> U-Boot console to restore it. Only a small percentage of users has
> the RS232 cable and the knowledge to do that.
> 
> And each time someone wants to change the distro, this changes
> the boot loader. This does not appear to be the right approach.
> 
Valid point. But maybe I should explain what I have in mind now:
I would like to have multiple distros on the GTA04.
1. one distro which I do not change and is in a well-known state and
   which I do not change. 
2. one distro which I can customize a lot and which behaves like I want.
3. one distro I want to try out and is maybe more comfortable than others
but is perhaps not that stable
4. Android (not for regular, daily use)

So when I notice that 2. or 3. has a problem I can go back to 1
without loosing any configuration and I can do it on the road.

At the moment I have configured uboot so that it shows a menu
to choose the partition when I select the MMC button. Then it
first looks in that partition for a /boot/boot.scr then /boot/uImage.bin and
then /boot/uImage. The root kernel parameter is set accordingly then.
So if the distro needs to really, really configure anything, it can be done
in that /boot/boot.scr without breaking the main uboot config.
And now I hope I never need to fiddle with the RS232 cable to fix uboot
problems.

I do not know how many of you have the same idea about setting up partitions,
but maybe these ideas are interesting for someone else. But, please do not
enforce the kernel commandline so that it is not possible to choose
the root parameter.

Greetings
Andreas Kemnade
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