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

[Paul Menzel <pmenzel@molgen.mpg.de>]

Dear Damien,


Am 01.04.22 um 09:23 schrieb Damien Le Moal:
> On 4/1/22 14:18, Paul Menzel wrote:

[…]

>> Am 01.04.22 um 01:04 schrieb Damien Le Moal:
>>> On 3/31/22 23:42, Paul Menzel wrote:
>>
>>>> Am 23.03.22 um 09:36 schrieb Paul Menzel:
>>>>
>>>>> Am 23.03.22 um 09:24 schrieb Damien Le Moal:
>>>>>> On 3/23/22 15:55, Paul Menzel wrote:
>>>>>
>>>>>>> Am 23.03.22 um 06:01 schrieb Damien Le Moal:
>>>>>>>> On 3/22/22 06:51, Limonciello, Mario wrote:
>>>>>
>>>>>>>>>> -----Original Message-----
>>>>>>>>>> From: Paul Menzel <pmenzel@molgen.mpg.de>
>>>>>>>>>> Sent: Monday, March 21, 2022 16:25
>>>>>>>
>>>>>>> […]
>>>>>>>
>>>>>>>>> I seem to recall that we were talking about trying to drop the
>>>>>>>>> debounce delay for everything, weren't we?
>>>>>>>>>
>>>>>>>>> So perhaps it would be right to add a 4th patch in the series to do
>>>>>>>>> just that.  Then If this turns out to be problematic for
>>>>>>>>> anything other than the controllers in the series that you
>>>>>>>>> identified as not problematic then that 4th patch can
>>>>>>>>> potentially be reverted alone?
>>>>>>>>
>>>>>>>> Not quite everything :) But you are right, let's try to switch the
>>>>>>>> default to no delay. I will be posting patches today for that.
>>>>>>>> With these patches, your patches are not necessary anymore as the AMD
>>>>>>>> chipset falls under the default no-delay.
>>>>>>>
>>>>>>> I am all for improving the situation for all devices, but I am unable to
>>>>>>> judge the regression potential of changing this, as it affects a lot of
>>>>>>> devices. I guess it’d would go through the next tree, and hopefully the
>>>>>>> company QA teams can give it a good spin. I hoped that my patches, as I
>>>>>>> have tested them, and AMD will hopefully too, could go into the current
>>>>>>> merge window.
>>>>>>
>>>>>> Yes, correct, the plan is to get the generic series queued as soon
>>>>>> as rc1 so that it can spend plenty of time in linux-next for people
>>>>>> to test. That will hopefully reduce the risk of breaking things in
>>>>>> the field. Same for  the default LPM change.
>>>>>
>>>>> But 5.18 or 5.19? If 5.18, sounds good to me, if 5.19, I’d be great if
>>>>> my patches go into 5.18 cycle, as they have been tested, and it would
>>>>> mean the whole change gets tested more widely already.
>>>>>
>>>>>> With the default removal of the debounce delay, your patches addressing
>>>>>> only the AMD adapter are not needed anymore: this adapter will not have a
>>>>>> debounce delay unless the ATA_LFLAG_DEBOUNCE_DELAY flag is set.
>>>>>
>>>>> Yes, I understand.
>>>>
>>>> The merge window for Linux 5.18 is going to close in three days this
>>>> Sunday. It’d be really great if my patches, tested on hardware, could go
>>>> into that.
>>>>
>>>>>>>> It would be nice if you can test though.
>>>>>>>
>>>>>>> Of course, I am going to that either way.
>>>>>>
>>>>>> Series posted with you on CC. Please test !
>>>>>
>>>>> Thank you. I am going to test it in the coming days, and report back.
>>>>>
>>>>> Maybe more people should be put in Cc (Dell, Lenovo, IBM, x86 subsystem)
>>>>> with a request to test this?
>>>> Thank you for the patches, which are a big improvement. Let’s hope, you
>>>> can re-roll them, so they get into Linux very soon for everyone’s benefit.
>>>
>>> I am waiting for 5.18-rc1 to rebase the patches and re-post them. Given
>>> reviewed-by and tested-by tags, I will queue them for 5.19.
>>
>> As discussed in the other thread, it’s impossible to be 100 % certain,
>> it won’t break anything.
> 
> Yes, that is why I want to push the patches early in the cycle to be able
> to revert if too many problems are reported.
> 
>>
>>> 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?


Kind regards,

Paul