linux-kernel - Re: [PATCH] i2c: i801: Prefer async probe

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Date:   Thu, 29 Sep 2022 17:43:34 +0200
From:   Jean Delvare <jdelvare@...e.de>
To:     Mani Milani <mani@...omium.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, linux-i2c@...r.kernel.org,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Wolfram Sang <wsa@...nel.org>
Subject: Re: [PATCH] i2c: i801: Prefer async probe

Hi Mani,

On Fri, 26 Aug 2022 17:44:30 +1000, Mani Milani wrote:
> This i801 driver probe can take more than ~190ms in some devices, since
> the "i2c_register_spd()" call was added inside
> "i801_probe_optional_slaves()".

Is there anything special about this 190 ms value?

> Prefer async probe so that other drivers can be probed and boot can
> continue in parallel while this driver loads, to reduce boot time. There is
> no reason to block other drivers from probing while this driver is
> loading.
> 
> Signed-off-by: Mani Milani <mani@...omium.org>
> ---
> 
>  drivers/i2c/busses/i2c-i801.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index a176296f4fff..e06509edc5f3 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1838,6 +1838,7 @@ static struct pci_driver i801_driver = {
>  	.shutdown	= i801_shutdown,
>  	.driver		= {
>  		.pm	= &i801_pm_ops,
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
>  	},
>  };
>  

Seems reasonable. I can't foresee any problem that would occur from
this change, and preliminary testing on my own workstation is OK.

Jarkko, Heiner, Wolfram, can you think of any reason why we should NOT
apply this change?

Thanks,
-- 
Jean Delvare
SUSE L3 Support