linux-kernel - Re: [PATCH v2 4/4] dell-wmi: Rework code for generating sparse keymap and processing WMI events

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Message-Id: <201606091333.49010@pali>
Date:	Thu, 9 Jun 2016 13:33:48 +0200
From:	Pali Rohár <pali.rohar@...il.com>
To:	Michał Kępień <kernel@...pniu.pl>
Cc:	Darren Hart <dvhart@...radead.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Gabriele Mazzotta <gabriele.mzt@...il.com>,
	Mario Limonciello <mario_limonciello@...l.com>,
	Andy Lutomirski <luto@...nel.org>,
	Alex Hung <alex.hung@...onical.com>,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/4] dell-wmi: Rework code for generating sparse keymap and processing WMI events

On Thursday 09 June 2016 13:27:21 Michał Kępień wrote:
> > > -		case 0x10:
> > > -			/* Keys pressed */
> > > +		case 0x0010:
> > > +			/* Sequence of keys pressed */
> > > 
> > >  			for (i = 2; i < len; ++i)
> > > 
> > > -				dell_wmi_process_key(buffer_entry[i]);
> > > +				dell_wmi_process_key(0x0010, buffer_entry[i]);
> > > 
> > >  			break;
> > > 
> > > -		case 0x11:
> > > -			for (i = 2; i < len; ++i) {
> > > -				switch (buffer_entry[i]) {
> > > -				case 0xfff0:
> > > -					/* Battery unplugged */
> > > -					pr_debug("Battery unplugged\n");
> > > -					break;
> > > -				case 0xfff1:
> > > -					/* Battery inserted */
> > > -					pr_debug("Battery inserted\n");
> > > -					break;
> > > -				case 0x01e1:
> > > -				case 0x02ea:
> > > -				case 0x02eb:
> > > -				case 0x02ec:
> > > -				case 0x02f6:
> > > -					/* Keyboard backlight level changed */
> > > -					pr_debug("Keyboard backlight level "
> > > -						 "changed\n");
> > > -					break;
> > > -				default:
> > > -					/* Unknown event */
> > > -					pr_info("Unknown WMI event type 0x11: "
> > > -						"0x%x\n", (int)buffer_entry[i]);
> > > -					break;
> > > -				}
> > > -			}
> > > +		case 0x0011:
> > > +			/* Sequence of events occurred */
> > > +			for (i = 2; i < len; ++i)
> > > +				dell_wmi_process_key(0x0011, buffer_entry[i]);
> > 
> > Since this is identical to case 0x010, let's avoid the duplication
> > of code and
> > 
> > handle this with a fall-through, like:
> > 		case 0x0010:
> > 		case 0x0011:
> > 			/* Sequence of events occurred */
> > 			for (i = 2; i < len; ++i)
> > 			
> > 				dell_wmi_process_key(buffer_entry[1], buffer_entry[i]);
> 
> I believe it was Pali's intention to make a distinction between keys
> being pressed (0x0010) and other events occuring (0x0011), so perhaps
> a comment after the first case label could be useful?
> 
>     case 0x0010:
>         /* Sequence of keys pressed; fall through */
>     case 0x0011:
>         /* Sequence of events occurred */
>         for (i = 2; i < len; ++i)
>             dell_wmi_process_key(buffer_entry[1], buffer_entry[i]);
> 
> I'll leave it to Pali to decide, I'm just throwing in my two cents.

Yes, that is truth, to visually distinguish between events and keys.

-- 
Pali Rohár
pali.rohar@...il.com

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