Re: [PATCH] libata-sff: fix 32-bit PIO regression

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Hugh Dickins wrote:

>> Commit 871af1210f13966ab911ed2166e4ab2ce775b99d (libata: Add 32bit PIO support)
>> caused all kind of errors on the ATAPI devices, so it's been empirically proven
>> that one shouldn't read/write an extra data word when a device isn't expecting
>> it already. "Don't do it then"; however still taking a chance to use 32-bit I/O
>> one last  time when there are exactly 3 trailing bytes.  Oh, and stop pointless
>> swapping bytes to and fro as well by using io*_rep() which shouldn't byte-swap.
>>
>> This should fix the kernel.org bug #12609.
>>
>> ---
>> This is hopefully better replacement for Hugh Dickins most recent patch
>> (http://marc.info/?l=linux-ide&m=123352294619281)...
>>     
>
> Yes, looks nice, and works for me.  My only criticism would be,
> minor issue unchanged by your patch, that actually "slop" isn't
> unlikely enough to deserve an "unlikely" - slop of 1 or 3 is
> unlikely, but slop of 2 is quite common.
>   

  Common on what types of ATAPI commands? I can hardly believe that they 
are common on the block I/O...

MBR, Sergei