RE: Question: where should the SCSI driver place MODE_SENSE data ?

[James Bottomley <James.Bottomley@SteelEye.com>]

On Wed, 2006-03-22 at 08:52 -0700, Ju, Seokmann wrote:
> On Tuesday, March 21, 2006 6:02 PM, James Bottomley wrote:
> > I don't understand the question.  Are you asking why
> > sd_read_write_protect_flag and sd_read_cache_type operate in the way
> > they do?  i.e. header first then actual data.
> For any SCSI command including MODE_SENSE, 'bufflen'in scsi_cmnd structure holds actual data buffer size in bytes if 'use_sg' flage is NOT set.
> The question is that "value of bufflen is 4 for the sd_read_cache_type operation and that is NOT sufficient to return header and page data by driver".
> If there is something that I misunderstood with the operation, please guide.

If you look at the functions in sd.c you'll see it goes about asking for
mode sense very carefully, because there are a lot of broken devices out
there.  The first request is only for enough of the headers to work out
the length of the page.

James


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