From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH v2 1/3] scsi: core: allow auto suspend override by low-level driver Date: Thu, 12 Sep 2019 14:43:44 +0100 Message-ID: <485731ed-d455-dbb2-0cd5-3110ff14f6b7@acm.org> References: <1568270135-32442-1-git-send-email-stanley.chu@mediatek.com> <1568270135-32442-2-git-send-email-stanley.chu@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1568270135-32442-2-git-send-email-stanley.chu@mediatek.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Stanley Chu , linux-scsi@vger.kernel.org, martin.petersen@oracle.com, avri.altman@wdc.com, alim.akhtar@samsung.com, pedrom.sousa@synopsys.com, sthumma@codeaurora.org, jejb@linux.ibm.com Cc: marc.w.gonzalez@free.fr, andy.teng@mediatek.com, chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com, evgreen@chromium.org, subhashj@codeaurora.org, linux-mediatek@lists.infradead.org, peter.wang@mediatek.com, vivek.gautam@codeaurora.org, matthias.bgg@gmail.com, linux-arm-kernel@lists.infradead.org, beanhuo@micron.com List-Id: linux-mediatek@lists.infradead.org On 9/12/19 7:35 AM, Stanley Chu wrote: > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 64c96c7828ee..461aafadd208 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -1300,7 +1300,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev) > device_enable_async_suspend(&sdev->sdev_gendev); > scsi_autopm_get_target(starget); > pm_runtime_set_active(&sdev->sdev_gendev); > - pm_runtime_forbid(&sdev->sdev_gendev); > + if (sdev->rpm_autosuspend_delay < 0) > + pm_runtime_forbid(&sdev->sdev_gendev); > pm_runtime_enable(&sdev->sdev_gendev); > scsi_autopm_put_target(starget); So we have a single new struct member, rpm_autosuspend_delay, that controls two different behaviors: (a) whether or not runtime suspend is enabled at device creation time and (b) the power management autosuspend delay. I don't like this. Should two separate variables be introduced instead of using a single variable to control both behaviors? > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index 202f4d6a4342..133b282fae5a 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -199,7 +199,7 @@ struct scsi_device { > unsigned broken_fua:1; /* Don't set FUA bit */ > unsigned lun_in_cdb:1; /* Store LUN bits in CDB[1] */ > unsigned unmap_limit_for_ws:1; /* Use the UNMAP limit for WRITE SAME */ > - > + int rpm_autosuspend_delay; > atomic_t disk_events_disable_depth; /* disable depth for disk events */ > > DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */ > Since the default value for the autosuspend delay is the same for all SCSI devices attached to a SCSI host is the same, please add a variable with the same name in the SCSI host template and use that value as the default value for SCSI devices. If the rpm_autosuspend_delay variable only occurs in struct scsi_device then LLD authors are forced to introduce a slave_configure function. Introducing such a function can be avoided if the default autosuspend delay can be specified in the host template. Bart.