Message-ID: <s5htx57hc89.wl-tiwai@suse.de>
Date:	Wed, 20 Aug 2014 09:05:58 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Andreas Mohr <andi@...as.de>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, Vojtech Pavlik <vojtech@...e.cz>,
	Jiri Kosina <jkosina@...e.cz>
Subject: Re: [PATCH 1/2] SOUND: kill gameport bits

At Tue, 19 Aug 2014 23:31:30 -0700,
Dmitry Torokhov wrote:
> 
> On Wed, Aug 20, 2014 at 08:09:49AM +0200, Takashi Iwai wrote:
> > At Tue, 19 Aug 2014 22:18:15 -0700,
> > Dmitry Torokhov wrote:
> > > 
> > > Hi Andreas,
> > > 
> > > On Wed, Aug 20, 2014 at 04:46:38AM +0200, Andreas Mohr wrote:
> > > 
> > > > Hi,
> > > > 
> > > > > Gameport support hasn't been working well ever since cpufreq became
> > > > > mainstream and it becomes increasingly hard to find hardware and
> > > > > software
> > > > > that would run on such old hardware.
> > > > 
> > > > Given that I'm puzzled why one would want to deprecate a whole subsystem
> > > > which appears to be supported by a whole 14 different PCI sound card
> > > > drivers (where the ones I'm owning hardware of are intended to be in
> > > > active maintenance)
> > > 
> > > 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)?
> > 
> > MPlayer and some programs have the joystick interface (even often
> > activated as default), IIRC.  I don't use it.  But I tested it
> > sometime ago.
> 
> But we are not dropping joystick support, you can still use USB, BT, etc
> joysticks. It is only gameport joysticks that I think are pretty much extinct
> by now.

They are dying, I agree.  But is it really extinct?  It's hard to
judge.

> > > > and only 3 ISA-based ones, I'm missing several
> > > > details and justifications of that decision here (perhaps there was a
> > > > prior discussion/activity that I'm missing?).
> > > 
> > > There was a post to linux-input a few days ago when I ased if anyone woudl cry
> > > over gameport going away.
> > 
> > Well, asking the usage in the devel ML isn't enough, I'm afraid.
> > ML is only for a small group of developers, where no user cares unless
> > they hit a problem.
> 
> That is true, but what is better venue? Even disabling in Kconfig won't help
> much as distros will re-enable it and users do not compile their own kernels.

I meant to statically disable Kconfig, or just "depends on BROKEN".
Only user who edits Kconfig and build the kernel can enable it again.

> > > > 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.
> > 
> > Hm, can't we just use the standard ktime for measuring the time diff?
> 
> We could use high-res timers, if they are available. Are they available on such
> old hardware and are they sufficiently fast to provide needed timings? I
> definitely do not have any hardware to est with.

The boards aren't necessarily bound with the old hardware.  PCI boards
run fine on the modern machines if they still have a PCI slot (how
lucky).  And, the highres timer itself isn't so new...

> > And, I guess only few programs care the speed parameter.
> 
> It is not programs that care about speed parameter, it is joystick kernel
> drivers that need it to time access.

OK.

> > > > 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.
> > > 
> > > > If we keep removing functionality like this, then why stop short of
> > > > removing x86 32bit as a whole? By having Linux support nicely restricted
> > > > to hardware made within the last 5 years, we would surely be doing the
> > > > planned-obsolescence Micro$oft "ecosystem" (what was ecological about
> > > > this again?) a huge favour...
> > > 
> > > I really do not care about Microsoft and favors, I just go by the fact that
> > > this hardware is becoming naturally extinct. And not only hardware, but also
> > > software that uses it. Do you still play a lot of games with joysticks on such
> > > hardware?
> > 
> > IMO, the number of users is less relevant for such an action.  Even if
> > there're only a few users, users do exist.
> > 
> > But, if the code maintenance becomes a too big burden, it's time to
> > think of code removal.  Is this the case?  Really difficult to keep
> > the code?
> 
> We can keep it, but it is pretty much broken, so why?

Well, it worked on my test machine a year ago or so.  Maybe I had a
good luck.

It's the gameport core code that is currently broken under some
situation, right?  If so, marking it as broken is the first step, and
we don't need to touch else.  We may fix it later, or we may not.  If
the thing isn't improved, then we can drop the whole stuff.


thanks,

Takashi
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