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scsi: sd: REQUEST SENSE for BLIST_IGN_MEDIA_CHANGE devices in runtime_resume()

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For SD card reader devices that have the BLIST_IGN_MEDIA_CHANGE flag
set, a MEDIUM MAY HAVE CHANGED unit attention is established after
resuming from runtime suspend. Send a REQUEST SENSE to consume the UA.

The "downside" is that for these devices we now rely on users to not
change the medium (SD card) *during* a runtime suspend/resume cycle,
i.e. when not unmounting.

To enable runtime PM for an SD cardreader (device number 0:0:0:0), do:

echo 0 > /sys/module/block/parameters/events_dfl_poll_msecs
echo 1000 > /sys/bus/scsi/devices/0:0:0:0/power/autosuspend_delay_ms
echo auto > /sys/bus/scsi/devices/0:0:0:0/power/control

[mkp: use scsi_device flag instead of poking at BLIST]

Link: https://lore.kernel.org/r/20210704075403.147114-3-martin.kepplinger@puri.sm
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Martin Kepplinger 2021-07-04 09:54:02 +02:00 committed by Martin K. Petersen
parent f591a2e054
commit ed4246d37f
1 changed files with 21 additions and 1 deletions
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22
drivers/scsi/sd.c
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@ -110,6 +110,7 @@ static void sd_shutdown(struct device *);
static int sd_suspend_system(struct device *);
static int sd_suspend_runtime(struct device *);
static int sd_resume(struct device *);
static int sd_resume_runtime(struct device *);
static void sd_rescan(struct device *);
static blk_status_t sd_init_command(struct scsi_cmnd *SCpnt);
static void sd_uninit_command(struct scsi_cmnd *SCpnt);
@ -604,7 +605,7 @@ static const struct dev_pm_ops sd_pm_ops = {
.poweroff = sd_suspend_system,
.restore = sd_resume,
.runtime_suspend = sd_suspend_runtime,
.runtime_resume = sd_resume,
.runtime_resume = sd_resume_runtime,
};
static struct scsi_driver sd_template = {
@ -3716,6 +3717,25 @@ static int sd_resume(struct device *dev)
return ret;
}
static int sd_resume_runtime(struct device *dev)
{
struct scsi_disk *sdkp = dev_get_drvdata(dev);
struct scsi_device *sdp = sdkp->device;
if (sdp->ignore_media_change) {
/* clear the device's sense data */
static const u8 cmd[10] = { REQUEST_SENSE };
if (scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL,
NULL, sdp->request_queue->rq_timeout, 1, 0,
RQF_PM, NULL))
sd_printk(KERN_NOTICE, sdkp,
"Failed to clear sense data\n");
}
return sd_resume(dev);
}
/**
* init_sd - entry point for this driver (both when built in or when
* a module).