Re: Changes to ide-probe.c in 2.6.9-rc2 causing improper detection

[Jens Axboe <axboe@suse.de>]

On Tue, Sep 14 2004, C.Y.M. wrote:
> 
> > 
> > On Mon, Sep 13 2004, C.Y.M. wrote:
> > > After installing 2.6.9-rc2 on my PC today (x86 VIA Chipset 
> > motherboard and
> > > Athlon XP CPU), The IDE detection during boot in probing 
> > for ide2-5 and
> > > displaying errors, and the hard drives that it does find 
> > are telling me that
> > > "hda: cache flushes not supported" (when they are displayed 
> > as supported
> > > when using 2.6.9-rc1.
> > 
> > Your drive doesn't advertise FLUSH_CACHE support, the model 
> > for when we
> > use these commands changed between -rc1 and -rc2. This 
> > essentially means
> > that you have to turn off write back caching for safe operations on a
> > journalled drive.
> > 
> > Alan, I bet there are a lot of these. Maybe we should consider letting
> > the user manually flag support for FLUSH_CACHE, at least it 
> > is in their
> > hands then.
> > 
> > -- 
> > Jens Axboe
> > 
> 
> Thanks for the explanation.  I can understand that some of the older drives
> will not support FLUSH_CACHE which is acceptable. On another note, since

They do support it, they just don't flag the support in the capability
flags. And of course some don't support it at all, you can try this on
your drives if you want to know for sure.

> most computers only have IDE0 and IDE1 slots, is there a way to prevent the
> probe from returning errors on boot when looking for IDE2 to IDE5?  Perhaps
> a kernel configuration option asking how many IDE's are expected to probe
> (defaulting to two)?

It is very annoying, I agree, I don't see the need to confuse people
with this message as well. Until that is fixed, you should be able to
use ide2=noprobe etc on the boot command line.

-- 
Jens Axboe