Re: [PATCH v2] drm/sitronix: move tiny Sitronix drivers to their own subdir

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi Javier, Marcus

Am 05.05.25 um 11:27 schrieb Javier Martinez Canillas:
> Thomas Zimmermann <tzimmermann@suse.de> writes:
>
> Hello Thomas,
>
>> Hi,
>>
>> there's one major issue here. You must not change the Kconfig symbols or
>> you'll break kernel updates for a lot of people. So those TINYDRM_* must
>> remain as is.
>>
> I disagree. The https://docs.kernel.org/admin-guide/abi.html document
> explictly states that Kconfig symbols are not an ABI, and userspace
> should not rely on these not changing over time.

To summarize our discussion on irc [1]: changing the symbols is ok, but 
we should make it compatible to ease the transition. To do so, the new 
Kconfig file can still contain the old Kconfig symbol and the new one 
defaults to it. Something like this:

config TINYDRM_ST7586
   tristate
   default n

config DRM_ST7586
   tristate "bla bla"
   ...
   default TINYDRM_ST7586

Doing 'make olddefconfig' or a similar make command sets the new symbol 
from the pre-existing one. After a few releases the old symbol can be 
removed.

Best regards
Thomas


[1] 
https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&highlight_names=&date=2025-05-05&show_html=true

>
>> Best regards
>> Thomas
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)