Re: [PATCH 1/2] SOUND: kill gameport bits

From: Vojtech Pavlik <vojtech@suse.cz>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andreas Mohr <andi@lisas.de>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jiri Kosina <jkosina@suse.cz>, Takashi Iwai <tiwai@suse.de>
Subject: Re: [PATCH 1/2] SOUND: kill gameport bits
Date: Wed, 20 Aug 2014 08:39:51 +0200	[thread overview]
Message-ID: <20140820063951.GA6791@suse.cz> (raw)
In-Reply-To: <20140820051815.GA1109@core.coreip.homeip.net>

On Tue, Aug 19, 2014 at 10:18:15PM -0700, Dmitry Torokhov wrote:

> Are you actively testing gameport interfaces with real joysticks/gamepads on
> these cards? And what software is still in use that runs on these old boxes
> (with mainline kernel)?

I still do have a huge box of gameport hardware in my office, it's just
that I haven't opened it for a number of years. However, if this thread
spurred enough interest in gameport devices, I would be willing to open
it and do the needed fixes.

If not, I think dropping makes sense. I still would shed a tear for all
those weird devices in the box, and possibly design an ATMega-based
USB<->Gameport adapter that actually works and supports even the digital
joysticks.

> > Also, I'm left wondering why e.g. my Athlon XP system (a very popular
> > choice for longer times) would be affected by Cpufreq...
> > And there are no details on how exactly cpufreq is a problem or how this
> > timing issue could be fixed...
> 
> If you take a look at gameport_measure_speed() in gameport.c you will see that
> it counts cycles for timing, which obviously does not work that well when CPU
> frequency changes.
> 
> The bugs have been opened in bugzilla/reported on lists ages ago but nobody
> stepped up to fix that.

It wouldn't be hard to fix: That code was developed when the timing
infrastructure in the kernel was non-existent, making use of it today
would make things a lot easier.

> > The obvious workaround for such an ensuing dearth of hardware support
> > could be USB 15-pin gameport adapters - but are they even supported on
> > Linux? Haven't seen info on this...
> > And even if supported, these adapters (at least the non-perfect ones, as
> > can be seen from reviews on a well-known online shop site) are said to
> > be hit-or-miss.
> > 
> > http://www.flightsim.com/vbfs/showthread.php?238938-joystick-GamePort-to-USB-adapter-question
> > http://reviews.thesource.ca/9026/2600164/nexxtech-usb-gameport-adapter-reviews/reviews.htm
> > 
> 
> They have better chance of being supported ;) I had a couple a few years back
> and they did work for me.

They do work for analog joysticks if you don't want any extended
functionality. I have a couple in said box.

-- 
Vojtech Pavlik
Director SuSE Labs