Re: [PATCH] MIPS: ingenic: Work around stale L2 data after DMA on XBurst II

[Hunter Laux <hunterlaux@gmail.com>]

Hi Nikolaus,

On Thu, Nov 12, 2026 at 11:24 +0100, H. Nikolaus Schaller wrote:
> - LX26 board with X2600 (isn't running stable for unknown reasons and
>                         sometimes damages the µSD contents but your
>                         patch didn't help to solve)

I don't know that the stale L2 data is behind your instability or µSD
problem. A quick way to rule it in or out, independent of the patch,
is to turn the prefetcher off (MSCR.DisPFB2):

  devmem 0x12200060 32 $(( $(devmem 0x12200060) | 2 ))

With it off I saw no stale reads here.

> Maybe the individuals and teams working on the XBurst devices should
> coordinate somehow to avoid double work and potentially incompatible
> fragments?

Agreed. I'll follow up off-list with what I have for the X2600.
What I have working on my board is here, on top of v7.3.3:

  https://github.com/jolting/linux/tree/ad5x-7.3.3-rc1

The patches I send upstream are cherry-picked from it.

I don't have any dev boards. My X2600 is in a Flashforge Adventurer 5X
3D printer, which is quite cheap, and its mainboard is also sold on its
own as a replacement part. A few of the printers make an X2600 test lab
that doubles as a print farm.

Hunter