Date: Tue, 22 Mar 2016 22:03:42 +0000 (GMT)
From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Borislav Petkov <bp@alien8.de>
cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        "Bryan O'Donoghue" <pure.logic@nexus-software.ie>,
        Andy Lutomirski <luto@amacapital.net>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Oleg Nesterov <oleg@redhat.com>,
        "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Subject: Re: [PATCH] x86/FPU: Fix FPU handling on legacy FPU machines
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On Fri, 11 Mar 2016, Borislav Petkov wrote:

> > Obvious Ack to the patch, along with a "how did this ever work
> > before?" comment..
> 
> I had a sarcastic sentence in the commit message which I deleted later:
> 
> "Apparently no one had tried the kernel on a 486er after the FPU
> rewrite. Backwards compatibility is overrated."

 People who care do not always have the resources to make regular tests 
with their hardware.

 I for once have meant to check the original series against my 486 EISA 
box since Ingo posted them back in May last year, and I still have them 
stashed away for this purpose.  Unfortunately I didn't get to wire that 
machine for remote console access and power supply control (and I have 
since run out of ports too), so I need to physically get to its location 
to do any testing.

 So it's not unusual for bugs in the less common configurations to only 
surface a bit later on, as people get to making an upgrade.  At least we 
have `git bisect' available and individual changes recorded now, which 
makes tracking down regressions a lot easier than it used to be in the old 
days.

  Maciej