Re: [PATCH 16/20] ata_piix: add EFAR SLC90E66 support

[Bartlomiej Zolnierkiewicz]

On Tue, Feb 8, 2011 at 2:13 PM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 08 Feb 2011 13:25:34 +0100
> Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx> wrote:
>
>> >From 11bed7feff5de752c9440ca58b232846b20e2ed6 Mon Sep 17 00:00:00 2001
>> From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
>> Date: Tue, 8 Feb 2011 12:39:28 +0100
>> Subject: [PATCH 16/20] ata_piix: add EFAR SLC90E66 support
>>
>> Add EFAR SLC90E66 support to ata_piix and remove no longer
>> needed pata_efar driver.
>
> Jeff specifically asked that these were not all folded into ata_piix
> originally. This also makes memory usage higher and the system less
> efficient as these are all motherboard chipsets (except an obscure dual
> PIIX4 setup) so you are loading more not less code.

A lot more from a generic SCSI code if you want to optimize things for
old or embedded systems. IMHO this is not a best place to look for
such optimizations because maintenance cost > potential savings (i.e.
making SCSI quirks optional, I have draft patch for this, itself cuts
like 10k).

> It also leads to hideous uglies in the main code paths like this :
>
> +       unsigned int has_sitre  = (dev->vendor != 0x8086 ||
> +                                  dev->device != 0x1230);
>
> which also has exactly zero comments.

has_sitre variable name is documentation in itself for anyone knowing
the hardware or has read a chipset/code documentation.

Though more comments can certainly be added if needed..
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