From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lin Ming Subject: Re: [RFC PATCH v2 8/8] [SCSI] sr: check and enable Zero-power ODD support Date: Fri, 02 Mar 2012 15:02:45 +0800 Message-ID: <1330671765.3412.7.camel@minggr> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga11.intel.com ([192.55.52.93]:25722 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756768Ab2CBHCs (ORCPT ); Fri, 2 Mar 2012 02:02:48 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Alan Stern Cc: Zhang Rui , Jeff Garzik , "Rafael J. Wysocki" , Tejun Heo , Aaron Lu , Kernel development list , linux-ide@vger.kernel.org, SCSI development list , Linux-pm mailing list , linux-acpi 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 example, adding a flag to libata.h ATA_DFLAG_ZPODD 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? > > Alan Stern >