Re: libata PATA todo list

[Bill Davidsen <davidsen@tmr.com>]

Jeff Garzik wrote:
> 
> Since there's been some recent interest in the subject, I thought I 
> would post the PATA todo list for libata.  Some of these items are from 
> my memory, and some are from a list Alan was kind enough to create.  The 
> items verbatim from Alan are prefixed "Alan: ".


> 2) Simplex DMA
> 
> PCI IDE specification has a 'simplex' DMA bit, which should be tested. 
> Simplex means that only one command can be outstanding, for BOTH port0 
> and port1, at any given time.
> 
> Possibly some hosts also need Simplex DMA, but may not assert the 
> standard PCI IDE Simplex DMA capability bit.  I don't know.

I remember using devices which require this. Not recently.


> 4) Alan:  Command filter
> 
> Alan -- explanation?
> 
> I know one line item here, at least:  Promise controllers snoop SET 
> FEATURES - XFER MODE command.  We must stop command processing on ALL 
> ports when this command is issued, to avoid corruption.

The last time I tried, cdrecord was allowed to burn the first session of 
a multi-session CD as a user (with correct device permissions) but not 
to read the multisession info (current ISO size) to burn another 
session. I haven't tried it in the last few months, I changed my script 
to do something else. However, it really should work.

I will test this if you like, but I'm on 7x24 coverage this week and 
7x24 vacation after that, so not soon.


> 10) ATAPI DMA alignment (discussed elsewhere)
> 
> Needed even for PATA, AFAICT.

Thanks for keeping the list!

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me