linux-kernel - Re: [PATCH 4/5] HSI: nokia-modem: drop support for disabled pm

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Date:	Sun, 31 Jan 2016 12:24:34 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	Sebastian Reichel <sre@...nel.org>
Cc:	Tony Lindgren <tony@...mide.com>,
	Benoît Cousson <bcousson@...libre.com>,
	Aaro Koskinen <aaro.koskinen@....fi>,
	Pavel Machek <pavel@....cz>, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
Subject: Re: [PATCH 4/5] HSI: nokia-modem: drop support for disabled pm

On Sunday 31 January 2016 02:19:46 Sebastian Reichel wrote:
> Disabled power management means, that the driver can only be
> used together with further out-of-tree kernel patches. There
> is no reason to support this in the mainline kernel and not
> having support for it means, that userspace can automatically
> detect if we are running kernel based power management.

Hi!

I'm against this change. It will break support for (patched) Maemo and 
proprietary Nokia sscd modem daemon.

Also you can export GPIOs manually via sysfs and touch that state. Which 
means that you can do power management with mainline kernel even if you 
set nokia-modem.pm=0. So please drop this patch.

> Signed-off-by: Sebastian Reichel <sre@...nel.org>
> ---
>  drivers/hsi/clients/nokia-modem.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hsi/clients/nokia-modem.c
> b/drivers/hsi/clients/nokia-modem.c index 1b4a250cf113..5e333eb82912
> 100644
> --- a/drivers/hsi/clients/nokia-modem.c
> +++ b/drivers/hsi/clients/nokia-modem.c
> @@ -33,7 +33,7 @@
>  static unsigned int pm = 1;
>  module_param(pm, int, 0400);
>  MODULE_PARM_DESC(pm,
> -	"Enable power management (0=disabled, 1=userland based [default],
> 2=kernel based)"); +	"Enable power management (1=userland based
> [default], 2=kernel based)");
> 
>  struct nokia_modem_device {
>  	struct tasklet_struct	nokia_modem_rst_ind_tasklet;
> @@ -198,6 +198,11 @@ static int nokia_modem_gpio_probe(struct device
> *dev) struct nokia_modem_device *modem = dev_get_drvdata(dev);
>  	int gpio_count, gpio_name_count, i, err;
> 
> +	if (pm != 1 && pm != 2) {
> +		dev_err(dev, "invalid pm configuration!");
> +		return -EINVAL;
> +	}
> +
>  	gpio_count = of_gpio_count(np);
> 
>  	if (gpio_count < 0) {

-- 
Pali Rohár
pali.rohar@...il.com

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