Messages in this thread Patch in this message | | | From | Martin Kepplinger <> | Subject | [PATCH v5 2/3] scsi: sd: send REQUEST SENSE for BLIST_MEDIA_CHANGE devices in runtime_resume() | Date | Wed, 30 Jun 2021 10:44:52 +0200 |
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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 <martin.kepplinger@puri.sm> --- drivers/scsi/sd.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 6d2d63629a90..b02378f40620 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -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 = { @@ -3720,6 +3722,28 @@ 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; + int timeout, res; + + timeout = sdp->request_queue->rq_timeout * SD_FLUSH_TIMEOUT_MULTIPLIER; + + if (sdp->sdev_bflags & BLIST_MEDIA_CHANGE) { + /* clear the devices' sense data */ + static const u8 cmd[10] = { REQUEST_SENSE }; + + res = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, + NULL, timeout, 1, 0, RQF_PM, NULL); + if (res) + 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). -- 2.30.2
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