linux-kernel - Re: [PATCH] firmware: add a function to load optional firmware v2

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Message-ID: <5AA5B93E.2060905@broadcom.com>
Date:   Mon, 12 Mar 2018 00:18:22 +0100
From:   Arend van Spriel <arend.vanspriel@...adcom.com>
To:     Andres Rodriguez <andresx7@...il.com>, linux-kernel@...r.kernel.org
Cc:     gregkh@...uxfoundation.org, mcgrof@...nel.org
Subject: Re: [PATCH] firmware: add a function to load optional firmware v2

On 3/10/2018 12:09 AM, Andres Rodriguez wrote:
> Currently the firmware loader only exposes one silent path for querying
> optional firmware, and that is request_firmware_direct(). This function
> also disables the usermodehelper fallback which might not always be the
> desired behaviour.
>
> This patch introduces request_firmware_optional(), which will not
> produce error/warning messages if the firmware file is not found, but
> will still attempt to query the usermodehelper for the optional
> firmware. Effectively, FW_OPT_UEVENT | FW_OPT_FALLBACK | FW_OPT_NO_WARN.
>
> v2: add header prototype, use updated opt_flags
>
> Signed-off-by: Andres Rodriguez <andresx7@...il.com>
> ---
>
> Sorry, I messed up the v1 patch and sent the wrong one from before I
> rebased.
>
>   drivers/base/firmware_class.c | 26 +++++++++++++++++++++++++-
>   include/linux/firmware.h      |  2 ++
>   2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index 7dd36ace6152..4e1eddea241b 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -1181,7 +1181,7 @@ static int fw_sysfs_fallback(struct firmware *fw, const char *name,
>   	if (!fw_run_sysfs_fallback(opt_flags))
>   		return ret;
>
> -	dev_warn(device, "Falling back to user helper\n");
> +	dev_warn(device, "Falling back to user helper for %s\n", name);

Helpful, but not really related to this change.

>   	return fw_load_from_user_helper(fw, name, device, opt_flags);
>   }
>   #else /* CONFIG_FW_LOADER_USER_HELPER */
> @@ -1351,6 +1351,30 @@ request_firmware(const struct firmware **firmware_p, const char *name,
>   }
>   EXPORT_SYMBOL(request_firmware);
>
> +/**
> + * request_firmware_optional: - request for an optional fw module
> + * @firmware_p: pointer to firmware image
> + * @name: name of firmware file
> + * @device: device for which firmware is being loaded
> + *
> + * This function is similar in behaviour to request_firmware(), except
> + * it doesn't produce warning messages when the file is not found.
> + **/
> +int
> +request_firmware_optional(const struct firmware **firmware_p, const char *name,
> +			  struct device *device)

So it still returns an error code. If it were truly optional I kinda 
expected a void return type. This is more request_firmware_silent(). 
Anyway, I guess Luis would call this bike-shedding ;-)

Regards,
Arend