Re: [PATCH v2] ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585

[Damien Le Moal <dlemoal@kernel.org>]

On 2026/04/03 21:17, Arthur Husband wrote:
> The JMicron JMB585 (and JMB582) SATA controllers advertise 64-bit DMA
> support via the S64A bit in the AHCI CAP register, but their 64-bit DMA
> implementation is defective. Under sustained I/O, DMA transfers targeting
> addresses above 4GB silently corrupt data — writes land at incorrect
> memory addresses with no errors logged.
> 
> The failure pattern is similar to the ASMedia ASM1061 (commit
> 2073d0e9b2778 ("ahci: add 43-bit DMA address quirk for ASMedia ASM1061
> controllers")), which also falsely advertised full 64-bit DMA support.
> However, the JMB585 requires a stricter 32-bit DMA mask rather than
> 43-bit, as corruption occurs with any address above 4GB.
> 
> On the Minisforum N5 Pro specifically, the combination of the JMB585's
> broken 64-bit DMA with the AMD Family 1Ah (Strix Point) IOMMU causes
> silent data corruption that is only detectable via checksumming
> filesystems (BTRFS/ZFS scrub). The corruption occurs when 32-bit IOVA
> space is exhausted and the kernel transparently switches to 64-bit DMA
> addresses.
> 
> Add device-specific PCI ID entries for the JMB582 (0x0582) and JMB585
> (0x0585) before the generic JMicron class match, using a new board type
> that combines AHCI_HFLAG_IGN_IRQ_IF_ERR (preserving existing behavior)
> with AHCI_HFLAG_32BIT_ONLY to force 32-bit DMA masks.
> 
> Signed-off-by: Arthur Husband <artmoty@gmail.com>

Looks OK to me.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research