Commit ed4246d3 authored by Martin Kepplinger's avatar Martin Kepplinger Committed by Martin K. Petersen
Browse files

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

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: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarMartin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent f591a2e0

drivers/scsi/sd.c

+21 −1
Original line number Diff line number Diff line
@@ -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).