2005-01-06 22:46:15

by Andrey Melnikoff

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Subject: Re: Questions about the CMD640 and RZ1000 bugfix support options

Alan Cox <[email protected]> wrote:
> On Mer, 2005-01-05 at 18:58, Andrey Melnikoff wrote:
> > > > At least the second of those two seems to cause some little slowdown
> > > > ("This may slow disk throughput by a few percent, but at least things
> > > They only trigger for the affected chipsets
> > But enabled by default. Maybe disable it by default ? Or make depend with
> > CONFIG_M586 || CONFIG_M586TSC || CONFIG_M586MMX ?

> They should be enabled by default.
Why? This is really _OLD_ and _BUGGY_ chips. As I see in google - it used
in Asustek Pentium MB PCI/I-P54SP4 and some Intel mb for Pentium with
Neptune chipsets. All of this MB - for classic Pentium 75/90/100MHz.

> That makes it safer for default compiles, and their code size is
> close to if not nil because it can all be __devinit or __init
At this time, no modern MB use this buggy chipsets.


2005-01-06 23:14:19

by Christoph Anton Mitterer

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Subject: Re: Questions about the CMD640 and RZ1000 bugfix support options

Andrey Melnikoff wrote:
> Alan Cox wrote:
> >They should be enabled by default.
>
> Why? This is really _OLD_ and _BUGGY_ chips. As I see in google - it used
> in Asustek Pentium MB PCI/I-P54SP4 and some Intel mb for Pentium with
> Neptune chipsets. All of this MB - for classic Pentium 75/90/100MHz.

What about the following idea?
Both stay enabled by default but the help text explains exactly (as
far as possible) which systems are affected.
This would help newbies like me to decide if those bugfixes are
necessary or not.

Greetings,
cam.

2005-01-07 00:51:52

by Christoph Anton Mitterer

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Subject: Re: Questions about the CMD640 and RZ1000 bugfix support options

Alan Cox wrote:

>On Iau, 2005-01-06 at 23:10, Christoph Anton Mitterer wrote:
>
>>What about the following idea?
>>Both stay enabled by default but the help text explains exactly (as
>>far as possible) which systems are affected.
>>This would help newbies like me to decide if those bugfixes are
>>necessary or not.
>
>
>Its the ideal solution. The diff for this is available on your computer
>already - its kept in /dev/null 8)

Ok,... so here's my patch which I request for inclusion:
--- begin of patch ---

--- end of patch ---
(Ahh,.. my first kernel patch,... *lol* )

;-)


Seriously,.. I thought about adding something like:
"Most users of modern computers won't need this, but it is safer to say
Y here."

But according to you answer I think that you like the way it's at the
moment. =)
Never mind! But if you think it's ok I could make a (real) patch which
adds such a text.

Best wishes,
cam.

2005-01-07 00:28:33

by Alan

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Subject: Re: Questions about the CMD640 and RZ1000 bugfix support options

On Iau, 2005-01-06 at 22:40, Andrey Melnikoff wrote:
> > They should be enabled by default.
> Why? This is really _OLD_ and _BUGGY_ chips. As I see in google - it used
> in Asustek Pentium MB PCI/I-P54SP4 and some Intel mb for Pentium with
> Neptune chipsets. All of this MB - for classic Pentium 75/90/100MHz.

And the cost to you is .. zero.

> > That makes it safer for default compiles, and their code size is
> > close to if not nil because it can all be __devinit or __init
> At this time, no modern MB use this buggy chipsets.

And lots of people run old motherboards. The base kernel configuration
by default is a mix between "things everyone wants, things defaulting on
for safety reasons and linus computer"

Alan

2005-01-07 00:28:34

by Alan

[permalink] [raw]
Subject: Re: Questions about the CMD640 and RZ1000 bugfix support options

On Iau, 2005-01-06 at 23:10, Christoph Anton Mitterer wrote:
> What about the following idea?
> Both stay enabled by default but the help text explains exactly (as
> far as possible) which systems are affected.
> This would help newbies like me to decide if those bugfixes are
> necessary or not.

Its the ideal solution. The diff for this is available on your computer
already - its kept in /dev/null 8)

The PC-Technologies RZ1000 IDE chip is used on many common 486
and
Pentium motherboards, usually along with the "Neptune"
chipset.
Unfortunately, it has a rather nasty design flaw that can
cause
severe data corruption under many conditions. Say Y here to
include
code which automatically detects and corrects the problem
under
Linux. This may slow disk throughput by a few percent, but at
least
things will operate 100% reliably.

The CMD-Technologies CMD640 IDE chip is used on many common
486 and
Pentium motherboards, usually in combination with a "Neptune"
or
"SiS" chipset. Unfortunately, it has a number of rather nasty
design flaws that can cause severe data corruption under many
common
conditions. Say Y here to include code which tries to
automatically
detect and correct the problems under Linux. This option also
enables access to the secondary IDE ports in some CMD640 based
systems.