Re: [PATCH v2 2/5] ata: ahci: a hotplug capable port is an external port

[Niklas Cassel <cassel@kernel.org>]

On Thu, Jun 13, 2024 at 07:33:09PM +0200, Thomas Weißschuh wrote:
> On 2024-06-13 17:37:51+0000, Niklas Cassel wrote:
> > On Thu, Jun 13, 2024 at 04:49:43PM +0200, Thomas Weißschuh wrote:
> > > On 2024-06-13 15:38:51+0000, Niklas Cassel wrote:
> > > > On Thu, Jun 13, 2024 at 03:13:54PM +0200, Niklas Cassel wrote:
> > > > > On Thu, Jun 13, 2024 at 05:29:31PM +0900, Damien Le Moal wrote:
> > > > > > On 6/13/24 15:34, Thomas Weißschuh wrote:
> > > > 
> > > > > I suggest that we:
> > > > > 1) Merge Damien's fix.
> > > > 
> > > > This might of course result in us getting other bug reports about their
> > > > distro no longer automounting their eSATA devices... and they might
> > > > consider that a user space regression as well.
> > > > (Since that behavior has now been there since 8a3e33cf92c7 ("ata: ahci:
> > > > find eSATA ports and flag them as removable"), which was merged in 2015.)
> > > 
> > > This is quite likely.
> > > 
> > > How about reverting the "ata: ahci: a hotplug capable port is an external"
> > > for now and work on a proper fix, including dev_set_removable() for an
> > > upcoming release?
> > 
> > Perhaps I'm missing something here, but how will dev_set_removable(),
> > which sets a different sysfs attibute solve that "problem"?
> 
> Indeed, it finally won't help.
> But only reverting that single commit should minimize the impact on
> users and give time to work on and discuss something better.

Reverting is not a good solution, because that means that we will not
disable LPM on hot-plug capable devices, which means that we will break
hot-plug. So that would be an even more serious bug :)

In my opinion, it seems quite clear that the current code is wrong
(at least according to the SPC-6 specification), so I see no reason
why we shouldn't just make the code spec compliant.

(and if a device is not spec complinant, it should be quirked.)

Damien, if you feel otherwise, please say so.


Kind regards,
Niklas