Commit 1df7ac86 authored by Martin Kepplinger's avatar Martin Kepplinger
Browse files

scsi: sd: send REQUEST SENSE for BLIST_MEDIA_CHANGE devices in runtime_resume()



For SD cardreader devices that have the BLIST_MEDIA_CHANGE flag set,
a MEDIA CHANGE unit attention is received after resuming from runtime
suspend. Send a REQUEST SENSE to avoid that.

The "downside" is that for these devices we now rely on users not to
really 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
Signed-off-by: Martin Kepplinger's avatarMartin Kepplinger <martin.kepplinger@puri.sm>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
parent f89641f2
......@@ -63,6 +63,7 @@
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
......@@ -114,6 +115,7 @@ 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);
......@@ -608,7 +610,7 @@ 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 = {
......@@ -3701,6 +3703,25 @@ 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->sdev_bflags & BLIST_MEDIA_CHANGE) {
/* clear the devices' 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).
......
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