linux-kernel - Re: [RFC] On the Current Troubles of Mainlining Loongson Platform Drivers

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Date:   Mon, 11 Feb 2019 20:38:00 -0200
From:   Alexandre Oliva <lxoliva@...la.org>
To:     Tom Li <tomli@...li.me>
Cc:     James Hogan <jhogan@...nel.org>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        Huacai Chen <chenhc@...ote.com>,
        Ralf Baechle <ralf@...ux-mips.org>, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC] On the Current Troubles of Mainlining Loongson Platform Drivers

On Feb 11, 2019, Tom Li <tomli@...li.me> wrote:

> What is the current link to your repository? 

git://dev.lemote.com/linux-loongson-community.git

I use a different git URL to push stuff, so I wouldn't have noticed if
the above was gone, but I've just tried to git clone form the above and
it seems to remain functional.

> We've just identified and confirmed the source of the shutdown problem a
> few days ago on this mailing list. It's related to a PREEMPT race condition
> in the cpufreq framework that triggers a timing-dependent, probabilistic
> lockup in the i8259 PIC driver. And it was first noticed by Ville Syrjälä
> on a x86 system, my debugging rediscovered his findings.

Oooh, thanks for the links.

>> and, more recently, a very slow system overall, that's been present since
>> 4.20.

> The mainline framebuffer driver doesn't have any hardware drawing, printing
> even a single line on the console is required a full screen redraw via memory-

That doesn't seem to explain even a quiet boot up taking several times
longer than 4.19, and package installation over an ethernet connection
(thus not using the console) also taking several times longer.

-- 
Alexandre Oliva, freedom fighter   https://FSFLA.org/blogs/lxo
Be the change, be Free!         FSF Latin America board member
GNU Toolchain Engineer                Free Software Evangelist
Hay que enGNUrecerse, pero sin perder la terGNUra jamás-GNUChe