RE: [PATCH v2 3/3] ata: ahci: Skip 200 ms debounce delay for AMD 300 Series Chipset SATA Controller

["Limonciello, Mario" <Mario.Limonciello@amd.com>]

[Public]



> -----Original Message-----
> From: Paul Menzel <pmenzel@molgen.mpg.de>
> Sent: Tuesday, September 13, 2022 10:23
> To: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Cc: Limonciello, Mario <Mario.Limonciello@amd.com>; Hans de Goede
> <hdegoede@redhat.com>; linux-ide@vger.kernel.org; LKML <linux-
> kernel@vger.kernel.org>
> Subject: Re: [PATCH v2 3/3] ata: ahci: Skip 200 ms debounce delay for AMD 300
> Series Chipset SATA Controller
> 
> Dear Damien,
> 
> 
> Am 01.09.22 um 00:13 schrieb Damien Le Moal:
> > On 8/30/22 18:05, Paul Menzel wrote:
> 
> […]
> 
> >> Am 01.06.22 um 10:58 schrieb Damien Le Moal:
> >>> On 6/1/22 01:18, Paul Menzel wrote:
> >>>>>>> With that in mind, I am not planning to apply your previous patches
> >>>>>>> for 5.18, as they would conflict and would only end up being churn
> >>>>>>> since the delay removal by default will undo your changes.
> >>>>>> Obviously, I do not agree, as this would give the a little bit more
> >>>>>> testing already, if changing the default is a good idea. Also, if the
> >>>>>> conflict will be hard to resolve, I happily do it (the patches could
> >>>>>> even be reverted on top – git commits are cheap and easy to handle).
> >>>>>
> >>>>> The conflict is not hard to resolve. The point is that my patches changing
> >>>>> the default to no debounce delay completely remove the changes of your
> >>>>> patch to do the same for one or some adapters. So adding your patches
> now
> >>>>> and then my patches on top does not make much sense at all.
> >>>>>
> >>>>> If too many problems show up and I end up reverting/removing the
> patches,
> >>>>> then I will be happy to take your patches for the adapter you tested. Note
> >>>>> that *all* the machines I have tested so far are OK without a debounce
> >>>>> delay too. So we could add them too... And endup with a long list of
> >>>>> adapters that use the default ahci driver without debounce delay. The
> goal
> >>>>> of changing the default to no delay is to avoid that. So far, the adapters
> >>>>> I have identified that need the delay have their own declaration, so we
> >>>>> only need to add a flag there. Simpler change that listing up adapters
> >>>>> that are OK without the delay.
> >>>>>
> >>>>>> Anyway, I wrote my piece, but you are the maintainer, so it’s your call
> >>>>>> and I stop bothering you.
> >>>>
> >>>> I just wanted to inquire about the status of your changes? I do not find
> >>>> them in your `for-5.19` branch. As they should be tested in linux-next
> >>>> before the merge window opens, if these are not ready yet, could you
> >>>> please apply my (tested) patches?
> >>>
> >>> I could, but 5.19 now has an updated libata.force kernel parameter that
> >>> allows one to disable the debounce delay for a particular port or for all
> >>> ports of an adapter. See libata.force=x.y:nodbdelay for a port y of
> >>> adapter x or libata.force=x:nodbdelay for all ports of adapter x.
> >>
> >> This is commit 3af9ca4d341d (ata: libata-core: Improve link flags forced
> >> settings) [1]. Thank you, this is really useful, but easily overlooked. ;-)
> >>
> >>> I still plan to revisit the arbitrary link debounce timers but I prefer to
> >>> have the power management cleanup applied first. The reason is that link
> >>> debounce depends on PHY readiness, which itself depends heavily on power
> >>> mode transitions. My plan is to get this done during this cycle for
> >>> release with 5.20 and then fix on top the arbitrary delays for 5.21.
> >>
> >> Nice. Can you share the current status?
> >
> > No progress. I need to put together a series with all the patches that
> > were sent already. Unless Mario can resend something ?
> 
> No reply from Mario.

I think what happened here is there was related patches from another party
that got tangled up with this.

> 
> >>> Is the libata.force solution OK for you until we have a final more solid
> >>> fix that can benefit most modern adapters (and not just the ones you
> >>> identified)? If you do have a use case that needs a "nodbdelay" horkage
> >>> due to some constraint in the field, then I will apply your patches, but
> >>> they likely will be voided by coming changes. Let me know.
> >>
> >> I think, applying the patch would be an improvement, as people wouldn’t
> >> need to update their Linux kernel command line, and I do not mind, if it
> >> gets reverted/dropped later.
> >
> > Let's see were the lpm stuff goes first.
> 
> It shouldn’t be too much hassle to adapt the lpm series after the patch
> is applied.
> 
> 
> Kind regards,
> 
> Paul