linux-kernel - Re: [PATCH v10 11/14] platform/x86: Split the alienware-wmi driver

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Message-ID: <Z6ufIQADzILVMusc@smile.fi.intel.com>
Date: Tue, 11 Feb 2025 21:04:01 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Kurt Borja <kuurtb@...il.com>
Cc: platform-driver-x86@...r.kernel.org,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Armin Wolf <W_Armin@....de>,
	Mario Limonciello <mario.limonciello@....com>,
	Hans de Goede <hdegoede@...hat.com>, Dell.Client.Kernel@...l.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 11/14] platform/x86: Split the alienware-wmi driver

On Tue, Feb 11, 2025 at 12:59:53PM -0500, Kurt Borja wrote:
> On Tue Feb 11, 2025 at 11:56 AM -05, Andy Shevchenko wrote:
> > On Fri, Feb 07, 2025 at 10:46:07AM -0500, Kurt Borja wrote:

...

> >>  obj-$(CONFIG_ALIENWARE_WMI)		+= alienware-wmi.o
> >>  alienware-wmi-objs			:= alienware-wmi-base.o
> >> +alienware-wmi-y				+= alienware-wmi-legacy.o
> >> +alienware-wmi-y				+= alienware-wmi-wmax.o
> >
> > Oh my... it's even inconsistent!
> 
> Again, this is an already used pattern:

> 	https://elixir.bootlin.com/linux/v6.14-rc2/source/drivers/platform/x86/dell/Makefile#L14
> 
> I add configuration entries later. Is the order of the changes wrong? or
> is it the entire approach? Do other modules here need a fix?

Again, it doesn't mean it's correct.

Maybe other modules also need that, I don't remember, but you may `git log
--no-merges --author="Andy" --grep objs` to see changes I made in the past.

...

> >> +	if (!ret) {
> >> +		if (out_data == 0)
> >> +			return sysfs_emit(buf, "[disabled] s5 s5_s4\n");
> >> +		else if (out_data == 1)
> >> +			return sysfs_emit(buf, "disabled [s5] s5_s4\n");
> >> +		else if (out_data == 2)
> >> +			return sysfs_emit(buf, "disabled s5 [s5_s4]\n");
> >
> > The whole code inherited same issues like redundant 'else'. Please, refactor.
> 
> This is not my code, so a separate patch would be needed.

Okay!

...

> >> +	if (strcmp(buf, "disabled\n") == 0)
> >> +		args.arg = 0;
> >> +	else if (strcmp(buf, "s5\n") == 0)
> >> +		args.arg = 1;
> >> +	else
> >> +		args.arg = 2;
> >
> > sysfs_match_string()
> 
> Same as above.

Same as above :-)

...

> >> +	if ((code & WMAX_THERMAL_TABLE_MASK) == WMAX_THERMAL_TABLE_USTT &&
> >> +	    (code & WMAX_THERMAL_MODE_MASK) <= THERMAL_MODE_USTT_LOW_POWER)
> >> +		return true;
> >> +
> >> +	return false;
> >
> > 	return ...
> >
> > but if you wish, this one is okay.
> 
> This was done for readibility. Also this would require a different
> patch.

No need, I'm fine with the current approach, just to show the alternatives.

...

> >> +	ret = wmax_thermal_information(priv->wdev, WMAX_OPERATION_SYS_DESCRIPTION,
> >> +				       0, (u32 *) &sys_desc);
> >
> > How do you guarantee an alignment? Yes, it might be good for the specific
> > hardware, but in general this is broken code.
> 
> This is a good question. I'm not really sure how to fix this tho. Is it
> fine to just pass a __packed struct? Also this would require another
> patch.

Usual approach here is to use one of get_unaligned_le32(), get_unaligned_be32()
depending on the byte ordering.

> >> +	if (ret < 0)
> >> +		return ret;

...

> >> +		set_bit(profile, choices);
> >
> > Do you need it to be atomic?
> 
> I don't think so. `choices` belongs to this thread only.

So, __set_bit() will suffice then.

...

> >> +void __exit alienware_wmax_wmi_exit(void)
> >> +{
> >> +	wmi_driver_unregister(&alienware_wmax_wmi_driver);
> >> +}
> >
> > Why not moving these boilerplate to ->probe() and use module_wmi_driver()?
> 
> This 3 files are a single module and it has two WMI drivers so this
> can't be used.

Can it be split to two separate modules then?

-- 
With Best Regards,
Andy Shevchenko