+ Shawn, Krzysztof, Conor Hi Tom,
On Wed, 28 Feb 2024 at 18:40, Tom Rini <tr...@konsulko.com> wrote: > > On Wed, Feb 28, 2024 at 10:09:13AM +0300, Dan Carpenter wrote: > > On Tue, Feb 27, 2024 at 04:40:01PM +0100, Sébastien Szymanski wrote: > > > Commit 5d7a95f49999 ("imx6ul/imx6ull: synchronise device trees with > > > linux") removed the display timings from the board device tree whereas > > > they are still needed by the mxsfb driver. > > > Add the timings back (the correct ones) in the > > > imx6ul-opos6uldev-u-boot.dtsi file and remove them from the > > > opos6uldev.env file. > > > > > > Update the opos6uldev_defconfig file so that the LCD turns on at boot. > > > > > > Fixes: 5d7a95f49999 ("imx6ul/imx6ull: synchronise device trees with > > > linux") > > > Signed-off-by: Sébastien Szymanski <sebastien.szyman...@armadeus.com> > > > > Huh. This is the commit that did that upstream. > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d9aa4d4fca67823838fe9861456201430c545e69 > > > > It's interesting how the timings in linux were always slightly different > > from in u-boot. > > Thanks for tracking that down, Dan. I'm adding in Sumit and Rob here > because this is a recent (rather than ancient) example of one of the > concerns about OF_UPSTREAM. I rather think about this as an opportunity to improve with OF_UPSTREAM. We can feed these kinds of DT ABI breakages to corresponding Linux kernel sub-arch maintainers. Especially once we move to OF_UPSTREAM and a sub-arch maintainer profile in Linux kernel to keep them aware that U-Boot should be considered too. > I think the commit in question can be > summarized as "remove a bunch of explicit HW information because there's > now a Linux Kernel driver that determines that dynamically". What do we > do next? The old information is in a presumably valid binding still, can > we just put it back and comment that consumers outside of Linux use this > still so it's not removed again later? Or am I just missing where we can > instead get this information from the DT still and not need to come up > with a new driver and subsystems? I can see following two paths forward: 1) Partially revert the Linux kernel commit to add back the display timings in DT. 2) Extend drivers/video/simple_panel.c in U-Boot to add support for compatible: "armadeus,st0700-adapt". If possible then I would be in favour of (2) rather than the current patch to do this properly. -Sumit > > -- > Tom