Re: Bug#1035587: linux: broken AHCI controller on MIPS Loongson 3 (regression from 5.10.162-1)

Cyril Brulebois <[email protected]> Sat, 6 May 2023 02:32:26 +0200

Newsgroups	gmane.linux.debian.ports.mips
Organization	Debian
Message-ID	<[email protected]>

Hi,

Knowing nothing about HW, MIPS, etc. as usual…

Aurelien Jarno <[email protected]> (2023-05-05):
> Following the point release, the buildd mipsel-osuosl-03.d.o does not
> boot anymore, with errors in the AHCI controller:
> 
> [   35.912147] ata4.00: exception Emask 0x0 SAct 0x20000000 SErr 0x0 action 0x6 frozen
> [   35.919769] ata4.00: failed command: WRITE FPDMA QUEUED
> [   35.924968] ata4.00: cmd 61/20:e8:00:f0:e1/00:00:00:00:00/40 tag 29 ncq dma 16384 out
> [   35.924968]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
> [   35.940097] ata4.00: status: { DRDY }
> [   35.943743] ata4: hard resetting link
> 
> While that initially looks like a hardware issue, it appears that
> reverting the kernel to 5.10.162-1 (from 5.10.178-3) fixes the issue.
> Strangely mipsel.osuosl-05.d.o, which seems to be similar hardware
> (CPU, motherboard and SATA drive), does not exhibit the same issue.

A quick search between both versions suggests 1 AHCI commit, and 2
Loongson ones, both in the PCI layer.

- ab711f3eda7a62c800b41997e818b675812f53a9 is AHCI, apparently
  Intel-only, so not interesting.
- 654ae539254d10042869fdc77ad04c09e7eff1fd and
  faa050d2ff8820f450b69b84645e74b6934ed5ad are abouts quirks, the first
  one adding them for LS7A, the second one extending that to more LS7A
  ports, and to LS2K.

Glancing at bootlog.txt, it seems both AHCI and PCI work together, and
that LS7A is involved, so maybe those two PCI commits are relevant? Why
the other similar machine isn't impacted, I don't know.

Direct links for commits in the linux-5.10.y branch:
 - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=654ae539254d10042869fdc77ad04c09e7eff1fd
 - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=faa050d2ff8820f450b69b84645e74b6934ed5ad


Cheers,
-- 
Cyril Brulebois ([email protected])            <https://debamax.com/>
D-I release manager -- Release team member -- Freelance Consultant

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