Hi Tom, > -----Original Message----- > From: Tom Rini <tr...@konsulko.com> > Sent: Wednesday, January 27, 2021 7:41 PM > To: Wasim Khan (OSS) <wasim.k...@oss.nxp.com> > Cc: s...@chromium.org; t-kri...@ti.com; Varun Sethi <v.se...@nxp.com>; u- > b...@lists.denx.de; Wasim Khan <wasim.k...@nxp.com> > Subject: Re: [PATCH] cmd: fdt: skip board specific fixup using env variable > > On Wed, Jan 27, 2021 at 02:09:48PM +0100, Wasim Khan wrote: > > > From: Wasim Khan <wasim.k...@nxp.com> > > > > Sometimes it is useful to boot OS with already fixed-up device tree. > > Check for env variable 'skip_board_fixup' > > before calling ft_board_setup(). > > Current behaviour is unchanged, additionally user can set > > skip_board_fixup to 1 to skip the fixup. > > > > Signed-off-by: Wasim Khan <wasim.k...@nxp.com> > > --- > > common/image-fdt.c | 17 ++++++++++++----- > > 1 file changed, 12 insertions(+), 5 deletions(-) > > Can you provide a specific example or two here? Thanks!
Thank you for your comments. Recently I faced issue where Linux crash in PCIe was observed in customer's env. Whereas same Linux was booting fine in my environment. After debugging we found that U-boot was doing fixup based on SVR value. SVR check was failing in customer's env because of different SoC personality which was causing the crash in OS. So I thought it is good idea to have an option to bypass U-boot fixup and use an already fixed-up device tree so that we can quickly check if the problem is in OS or it is caused because of missed/wrong fixup from Uboot. Another use case I can think of is suppose if we want to introduce a new dtb fixup , we can directly add the change in a fixed-up device tree, do all experiments and once validated thoroughly , we can do the same change via Uboot fixup.
