On Tue, 2 Dec 2025 13:51:59 +0200 Tomi Valkeinen <[email protected]> wrote:
> Hi Kory, > > On 02/12/2025 13:18, Kory Maincent wrote: > > On Tue, 2 Dec 2025 11:47:40 +0100 > > Krzysztof Kozlowski <[email protected]> wrote: > I will not NAK, removing bindings and breaking users is under some > conditions acceptable. You just need to come with the reasons and impact. > > Reason "is ugly" is usually not good enough. Especially if things were > working. Thanks for you reply. > >> > >> DTS cannot go to drm, which means you either need to separate the change > >> and make entire work bisectable and backwards compatible for some time > >> OR at least document clearly the impact as we always ask. > > > > The thing is, if I split it, it has to be in 3. One for the of DRM bus flags > > support, a second for the the devicetree and binding change and a third for > > the whole tilcdc and tda998x cleaning stuff. I think I will go for one > > series, with better documentation. > > > > Now, what is your point of view on my question. Will you nak any binding > > removal even if the binding is ugly and legacy and imply maintaining an > > non-standard tilcdc panel driver? I know it breaks DTB compatibility but > > there is several argument to not keep it. See patch 6. > The binding being ugly and having to maintain non-standard tilcdc panel > driver may be nice things for us, the users don't care. The users care > if their board no longer works. Yes I understand but then I have another question. At what cost should we continue to support legacy binding? Just figured out this case already happened, ti,tilcdc,slave binding was removed from the tilcdc driver: 739acd85ffdb7 ("drm/tilcdc: Remove obsolete "ti,tilcdc,slave" dts binding support") Even if there is still one mainline device tree that uses it: am335x-base0033.dts. :/ > And how does this sync with u-boot? It also has code for at least for a > few of these boards. U-boot has indeed a driver for the ti,tilcdc,panel binding. Changing this devicetree would beak display for these board in U-boot as it currently does not support the "panel-dpi" binding. > Are there even users for these boards? If not, maybe they can be just > removed? I'm personally not familiar with these boards, so I have no > idea of their age or distribution. These boards are quite old (>10 years) but I don't know if they are still used by people. After a quick look they seem not available on the market. > One trick that can be done is to modify the loaded DTB at boot time, > detecting the old format, converting it to the new one, so that when the > drivers are probed they only see the new DTB. Yes, indeed that could do the trick. The things is, I don't have one of theses board to test it. I will try to look for an other way to test it. Regards, -- Köry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com
