Re: [PATCH v5 1/6] ata: libata-scsi: add atapi_max_lun module parameter

[Damien Le Moal]

On 2026/05/12 22:27, Phil Pemberton wrote:
> Until now libata has hard-coded shost->max_lun = 1 for every ATA host,
> so the SCSI layer never scans past LUN 0.  This blocks support for
> the small handful of multi-LUN ATAPI devices (Panasonic LF-1195C and
> COMPAQ PD-1 PD/CD combos export CD on LUN 0 and PD on LUN 1; old
> Nakamichi MJ-x.y CD changers expose one LUN per disc slot, up to 7).
> 
> Introduce a libata module parameter, atapi_max_lun, that controls the
> upper bound of the per-host SCSI LUN scan.  Default is 1, preserving
> current behaviour exactly: out-of-the-box only LUN 0 is scanned.
> Range is clamped to 1..ATAPI_MAX_LUN (8, the SCSI-2 ceiling).
> 
> Subsequent patches gate actual LUN>0 probing on BLIST_FORCELUN, so a
> device must both be on the SCSI device list (or carry the appropriate
> quirk) and run on a host whose atapi_max_lun has been raised before
> any extra LUNs are scanned.
> 
> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
> Signed-off-by: Phil Pemberton <philpem@xxxxxxxxxxxxx>

This looks OK to me:

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


-- 
Damien Le Moal
Western Digital Research