Re: [PATCH] platform/surface: aggregator: Fix initialization order when compiling as builtin module

[Hans de Goede]

Hi,

On 4/29/22 21:57, Maximilian Luz wrote:
> When building the Surface Aggregator Module (SAM) core, registry, and
> other SAM client drivers as builtin modules (=y), proper initialization
> order is not guaranteed. Due to this, client driver registration
> (triggered by device registration in the registry) races against bus
> initialization in the core.
> 
> If any attempt is made at registering the device driver before the bus
> has been initialized (i.e. if bus initialization fails this race) driver
> registration will fail with a message similar to:
> 
>     Driver surface_battery was unable to register with bus_type surface_aggregator because the bus was not initialized
> 
> Switch from module_init() to subsys_initcall() to resolve this issue.
> Note that the serdev subsystem uses postcore_initcall() so we are still
> able to safely register the serdev device driver for the core.
> 
> Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
> Reported-by: Blaž Hrastnik <blaz@xxxxxxx>
> Signed-off-by: Maximilian Luz <luzmaximilian@xxxxxxxxx>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans



> ---
>  drivers/platform/surface/aggregator/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
> index d384d36098c2..a62c5dfe42d6 100644
> --- a/drivers/platform/surface/aggregator/core.c
> +++ b/drivers/platform/surface/aggregator/core.c
> @@ -817,7 +817,7 @@ static int __init ssam_core_init(void)
>  err_bus:
>  	return status;
>  }
> -module_init(ssam_core_init);
> +subsys_initcall(ssam_core_init);
>  
>  static void __exit ssam_core_exit(void)
>  {