Messages in this thread | | | Date | Fri, 2 Mar 2012 23:08:10 +0800 | Subject | Re: [RFC PATCH v2 8/8] [SCSI] sr: check and enable Zero-power ODD support | From | Aaron Lu <> |
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Hi,
On Fri, Mar 2, 2012 at 3:02 PM, Lin Ming <ming.m.lin@intel.com> 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)? 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.
-Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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