Re: [PATCH 1/2] fbdev/offb: Update expected device name

On Thu, Jun 15, 2023 at 03:21:07PM +0200, Michal Suchánek wrote:

quoted

At the time this was proposed it was said that "of-display", is wrong,
and that "of-display.0" must be used for the first device instead, and
if something breaks an alias can be provided.

So how does one provide an alias so that offb can find "of-display.0"
as "of-display"?

I'm not aware of any way. There isn't because device names and paths are 
not considered ABI. There are mechanisms for getting stable class device 
indices (e.g. i2c0, mmcblk0, fb0, fb1, etc.) though not implemented for 
fbN (and please don't add it). 

In any case, this should be an easy fix. Though if "linux,opened" or 
"linux,boot-display" is not set, then you'd still get "of-display.0":

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 78ae84187449..e46482cef9c7 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c

@@ -553,7 +553,7 @@ static int __init of_platform_default_populate_init(void)
                        if (!of_get_property(node, "linux,opened", NULL) ||
                            !of_get_property(node, "linux,boot-display", NULL))
                                continue;
-                       dev = of_platform_device_create(node, "of-display.0", NULL);
+                       dev = of_platform_device_create(node, "of-display", NULL);
                        of_node_put(node);
                        if (WARN_ON(!dev))
                                return -ENOMEM;