From c95e948870bdfc606946174facd9ea359ce84e58 Mon Sep 17 00:00:00 2001 From: Svyatoslav Ryhel Date: Thu, 25 Jan 2024 22:16:54 +0200 Subject: boot: pxe_utils: skip fdt setup in case legacy kernel is booted MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, if boot with extlinux.conf and do not set the fdt U-Boot will provide its own device tree. This behavior is beneficial if the U-Boot device tree is in sync with Linux, but it totally halts the booting of pre-dtb kernels (3.4 for example) since it uses ATAGs. To fix this, pass `-` in the fdt extlinux field as a signal that no tree should be used. Suggested-by: Jonas Schwöbel Tested-by: Jethro Bull Signed-off-by: Svyatoslav Ryhel --- doc/develop/distro.rst | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'doc/develop') diff --git a/doc/develop/distro.rst b/doc/develop/distro.rst index 8016acad098..9e715b23ebb 100644 --- a/doc/develop/distro.rst +++ b/doc/develop/distro.rst @@ -81,6 +81,12 @@ as specified at `Boot Loader Specification`_: * Does not document the fdtdir option, which automatically selects the DTB to pass to the kernel. +* If no fdt/fdtdir is provided, the U-Boot will pass its own currently used + device tree. + +* If ``-`` is passed as fdt argument and ``CONFIG_SUPPORT_PASSING_ATAGS`` is + enabled, then no device tree will be used (legacy booting / pre-dtb kernel). + See also doc/README.pxe under 'pxe file format'. One example extlinux.conf generated by the Fedora installer is:: -- cgit v1.2.3