Re: [PATCH v2] ata: libata-pmp: add JMicron JMS562 quirk

[Damien Le Moal]

On 2026/06/10 13:28, raoxu wrote:
> From: Xu Rao <raoxu@xxxxxxxxxxxxx>
> 
> JMicron JMS562, as used in QNAP QDA-A2AR RAID1 adapters, may
> keep the exported ATA device not ready while the array is rebuilding.
> 
> In this state, libata may repeatedly try to softreset and classify
> the fan-out link.  On the affected adapter, this can time out, make
> PMP/SCR access fail, and eventually disable the fan-out link before
> the RAID volume is exported.
> 
> A failing boot shows the fan-out link failing SRST, PMP access
> timing out, SCR read failing, and the link being disabled:
> 
>   ata4.00: softreset failed (device not ready)
>   ata4.15: qc timeout after 3000 msecs (cmd 0xe4)
>   ata4.00: failed to read SCR 0 (Emask=0x4)
>   ata4.00: failed to recover link after 3 tries, disabling
> 
> After that, the root filesystem on the exported RAID volume cannot
> be found.
> 
> Add JMS562 to the existing JMicron PMP quirk that disables LPM,
> avoids softreset on fan-out links, and assumes an ATA device.  This
> prevents libata from dropping the exported RAID volume during rebuild
> recovery.
> 
> Signed-off-by: Xu Rao <raoxu@xxxxxxxxxxxxx>

It is really unfortunate that JMicron keeps having these issues. But I do not
see any way around this, so:

Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>


-- 
Damien Le Moal
Western Digital Research