Re: [patch ide-dev 8/9] make ide_task_ioctl() use REQ_DRIVE_TASKFILE

[Bartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>]

On Sunday 27 February 2005 08:36, Tejun Heo wrote:
>  Hello, Bartlomiej.
> 
>  This patch should be modified to use flagged taskfile if the
> task_end_request_fix patch isn't applied.  As non-flagged taskfile
> won't return valid result registers, TASK ioctl users won't get the
> correct register output.

Nope, it works just fine because REQ_DRIVE_TASK used only
no-data protocol, please check task_no_data_intr().

>  IMHO, this flag-to-get-result-registers thing is way too subtle.  How
> about keeping old behavior by just not copying out register outputs in
> ide_taskfile_ioctl() in applicable cases instead of not reading
> registers when ending commands?  That is, unless there's some
> noticeable performance impacts I'm not aware of.

This would miss whole point of not _reading_ these registers (IO is slow).
IMHO new flags denoting {in,out} registers should be added (to <linux/ata.h>
to share them with libata) so new code can be sane and old flags would map
on new flags when needed.