Re: kern/58767: VT6421 is not working

["Andrius V via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/58767; it has been noted by GNATS.

From: Andrius V <vezhlys%gmail.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/58767: VT6421 is not working
Date: Wed, 12 Mar 2025 16:07:19 +0200

 On Tue, Mar 11, 2025 at 6:18=E2=80=AFPM Andrius V <vezhlys%gmail.com@localhost> wrote=
 :
 >
 > On Mon, Oct 21, 2024 at 1:46=E2=80=AFPM <bogdan%kde.org@localhost> wrote:
 > >
 > > [  1924.584579] wd0: autoconfiguration error: excessive DMA errors - 4 =
 in last 30 transfers
 > > [  1924.606353] wd0c: error reading fsbn 68 of 68-71 (wd0 bn 68; cn 0 t=
 n 1 sn 5), xfer 40, retry 0
 > > [  1924.606353] wd0: (aborted command, interface CRC error)
 > > [  1925.754578] wd0: soft error (corrected) xfer 40
 > > [  1926.084581] wd0c: error reading fsbn 336 of 336-339 (wd0 bn 336; cn=
  0 tn 5 sn 21), xfer 40, retry 0
 > > [  1926.084581] wd0: (aborted command, interface CRC error)
 > > [  1926.614578] wd0: soft error (corrected) xfer 40
 > > [...]
 > > lots of wd0 errors.
 > >
 > > >How-To-Repeat:
 >
 > Hi,
 >
 > It can be SPARC or SSD specific issue, I am using it relatively
 > successfully on the x86/amd64 system.
 >
 > However, this controller is quite fickle from my experience. I've seen
 > quite similar errors because of "bad" SATA cables or maybe power
 > connectors.
 >
 > Of course, if Linux consistently works correctly with the same device,
 > likely the problem is elsewhere.
 
 
 It seems to be specific to the attached device (not arch) and I can
 actually reproduce this after prolonged usage or writes with the SSD
 drive.
 
 Linux apparently had the same problem, some "magic" fix was applied,
 which slows down the disk speed but makes it work stable for those
 "incompatible" disks (commits below all related to it):
 https://github.com/torvalds/linux/commit/8b27ff4cf6d15964aa2987aeb58db4dfb1=
 f87a19
 https://github.com/torvalds/linux/commit/b475a3b83a7709e16a734ef2b8ead4d50f=
 885427
 https://github.com/torvalds/linux/commit/b1353e4f40f6179ab26a3bb1b2e1fe29ff=
 e534f5
 https://github.com/torvalds/linux/commit/44a9b494f20b37dc9c9f94577ff98c856f=
 594b96
 
 I will try to analyze these commits (or maybe somebody else can?) and
 see if it is actually relevant to us and if it can be applied in
 NetBSD.
 
 It seems they apply this to VT6420 (meaning likely to VT8237R
 integrated controller since it shares pci id afaik). I was using it
 for years, but likely with "compatible" drive.
 Would need to test same SSD and see if issue reoccurs there too.
 
 Regards,
 Andrius V