On Fri, 2012-03-02 at 23:08 +0800, Aaron Lu wrote: > Hi, > > On Fri, Mar 2, 2012 at 3:02 PM, Lin Ming <ming.m.lin@xxxxxxxxx> wrote: > > On Thu, 2012-03-01 at 11:02 -0500, Alan Stern wrote: > >> On Thu, 1 Mar 2012, Lin Ming wrote: > >> > >> > ZPODD(Zero Power Optical Disk Drive) is a new feature in > >> > SATA 3.1 specification. It provides a way to power off unused ODD. > >> > > >> > ZPODD support is checked in in sr_probe(). > >> > can_power_off flag is set during suspend if ZPODD is supported. > >> > > >> > ATA port's runtime suspend callback will actually power off the ODD > >> > and its runtime resume callback will actually power on the ODD. > >> > > >> > When ODD is powered off(D3Cold state), inserting disk will trigger a > >> > wakeup event(GPE). GPE AML handler notifies the associated device. Then > >> > ODD is resumed in the notify handler. > >> > >> I have one stylistic comment on this patch... > >> > >> > diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h > >> > index 37c8f6b..39b3d8c 100644 > >> > --- a/drivers/scsi/sr.h > >> > +++ b/drivers/scsi/sr.h > >> > @@ -42,6 +42,9 @@ typedef struct scsi_cd { > >> > unsigned readcd_cdda:1; /* reading audio data using READ_CD */ > >> > unsigned media_present:1; /* media is present */ > >> > > >> > + unsigned zpodd:1; /* is ZPODD supported */ > >> > + unsigned zpodd_event:1; > >> > + > >> > >> You should not expect your readers to understand what "ZPODD" means. > >> drivers/scsi/sr.h is used by lots of different people, many of whom > >> will have no idea what it refers to, especially since it is part of > >> the SATA spec and not the SCSI spec. You should provide a brief > >> explanation. > > > > I'll add some explanation. > > > > But I'm thinking maybe it's better to move this flag to ata layer, for > > Agree. > > > example, adding a flag to libata.h > > > > ATA_DFLAG_ZPODD > > > > How about ATA_DFLAG_DA(device attention)? Yes, it's better. > It follows the name used in the sata spec and this feature might have > other uses in the future in addition to zero power odd(just my wild guess). > > > sr runtime pm is only enabled when ZPODD(or more general, power off) is > > supported. > > So the problem is how will sr driver know this flag? > > > > What about adding a new field to scsi_device to reflect this capability of > the underlying sata device? We can then set this field in ata_scsi_scan_host. Nice idea. I'll refresh this patch. Thanks, Lin Ming -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html