Re: [PATCH] PCI: xgene: Fix IB window setup #forregzbot

[Thorsten Leemhuis <regressions@leemhuis.info>]

TWIMC: this mail is primarily send for documentation purposes and for
regzbot, my Linux kernel regression tracking bot. These mails usually
contain '#forregzbot' in the subject, to make them easy to spot and filter.

Forwarding a few details from here:
https://lore.kernel.org/regressions/CAL_JsqLHun+X4jMwTbVMmjjETfbP73j52XCwWBj9MJCkpQ41mA@mail.gmail.com/

#regzbot introduced: 6dce5aa59e0b
#regzbot title: c7a75d07827a fixed 6dce5aa59e0b for XGene2, but that
*further* broke XGene1
#regzbot backburner: needs more debugging and number of people who care
likely small anyway

On 06.02.22 10:52, Thorsten Leemhuis wrote:
> [TLDR: I'm adding the regression report below to regzbot, the Linux
> kernel regression tracking bot; nearly all text you find below is
> compiled from a few templates paragraphs you likely have encountered
> already already from mails similar to this one.]
> 
> Hi, this is your Linux kernel regression tracker speaking.
> 
> CCing the regression mailing list, as it should be in the loop for all
> regressions, as explained here:
> https://www.kernel.org/doc/html/latest/admin-guide/reporting-issues.html
> 
> On 05.02.22 00:01, dann frazier wrote:
>> On Mon, Nov 29, 2021 at 11:36:37AM -0600, Rob Herring wrote:
>>> Commit 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup")
>>> broke PCI support on XGene. The cause is the IB resources are now sorted
>>> in address order instead of being in DT dma-ranges order. The result is
>>> which inbound registers are used for each region are swapped. I don't
>>> know the details about this h/w, but it appears that IB region 0
>>> registers can't handle a size greater than 4GB. In any case, limiting
>>> the size for region 0 is enough to get back to the original assignment
>>> of dma-ranges to regions.
>>
>> hey Rob!
>>
>> I've been seeing a panic on HP Moonshoot m400 cartridges (X-Gene1) -
>> only during network installs - that I also bisected down to commit
>> 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup"). I was
>> hoping that this patch that fixed the issue on Stéphane's X-Gene2
>> system would also fix my issue, but no luck. In fact, it seems to just
>> makes it fail differently. Reverting both patches is required to get a
>> v5.17-rc kernel to boot.
>>
>> I've collected the following logs - let me know if anything else would
>> be useful.
>>
>> 1) v5.17-rc2+ (unmodified):
>>    http://dannf.org/bugs/m400-no-reverts.log
>>    Note that the mlx4 driver fails initialization.
>>
>> 2) v5.17-rc2+, w/o the commit that fixed Stéphane's system:
>>    http://dannf.org/bugs/m400-xgene2-fix-reverted.log
>>    Note the mlx4 MSI-X timeout, and later panic.
>>
>> 3) v5.17-rc2+, w/ both commits reverted (works)
>>    http://dannf.org/bugs/m400-both-reverted.log
> 
> Thanks for the report.
> 
> To be sure this issue doesn't fall through the cracks unnoticed, I'm
> adding it to regzbot, my Linux kernel regression tracking bot:
> 
> #regzbot ^introduced c7a75d07827a1f33d
> #regzbot title Follow-up error for the commit fixing "PCIe regression on
> APM Merlin (aarch64 dev platform) preventing NVME initialization"
> #regzbot ignore-activity
> 
> Reminder for developers: when fixing the issue, please add a 'Link:'
> tags pointing to the report (the mail quoted above) using the
> lore.kernel.org/r/, as explained in
> 'Documentation/process/submitting-patches.rst' and
> 'Documentation/process/5.Posting.rst', as this allows the bot to assign
> any fixes posted or commited with the report to always show the current
> status of things and automatically close the issue when the fix hits the
> right tree.
> 
> I'm sending this to everyone that got the initial report, to make them
> aware of the tracking. I also hope that messages like this motivate
> people to directly get at least the regression mailing list and ideally
> even regzbot involved when dealing with regressions, as messages like
> this wouldn't be needed then.
> 
> Don't worry, I'll send further messages wrt to this regression just to
> the lists (with a tag in the subject so people can filter them away), if
> they are relevant just for regzbot. With a bit of luck no such messages
> will be needed anyway.
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> 
> P.S.: As the Linux kernel's regression tracker I'm getting a lot of
> reports on my table. I can only look briefly into most of them and lack
> knowledge about most of the areas they concern. I thus unfortunately
> will sometimes get things wrong or miss something important. I hope
> that's not the case here; if you think it is, don't hesitate to tell me
> in a public reply, it's in everyone's interest to set the public record
> straight.
>