| Message ID | 20210630084453.186764-1-martin.kepplinger@puri.sm |
|---|---|
| Headers | show |
| Series | fix runtime PM for SD card readers | expand |
On Wed, Jun 30, 2021 at 10:44:52AM +0200, Martin Kepplinger wrote: > + 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; Is REQUEST SENSE reqlly a so slow operation on these devices that we need to override the timeout?
hi, (According to Alan Stern, "as far as I know, all") SD card readers send MEDIA_CHANGED unit attention notification on (runtime) resume. We cannot use runtime PM with these devices as I/O always fails in that case. This fixes runtime PM for SD cardreaders. I'd appreciate any feedback. To enable runtime PM for an SD cardreader 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 thank you, martin revision history ---------------- v5: (thank you Bart) * simplify the sense request itself and remove unnecessary code v4: (thank you Bart and Alan) * send SENSE REQUEST in sd instead of adding a global scsi error flag. https://lore.kernel.org/linux-scsi/20210628133412.1172068-1-martin.kepplinger@puri.sm/T/#t v3: (thank you Bart) * create a new BLIST entry to mark affected devices instead of the sysfs module parameter for sd only. still, only sd implements handling the flag for now. * cc linux-pm list https://lore.kernel.org/linux-scsi/20210328102531.1114535-1-martin.kepplinger@puri.sm/ v2: https://lore.kernel.org/linux-scsi/20210112093329.3639-1-martin.kepplinger@puri.sm/ * move module parameter to sd * add Documentation v1: https://lore.kernel.org/linux-scsi/20210111152029.28426-1-martin.kepplinger@puri.sm/T/ For the full background, the discussion started in June 2020 here: https://lore.kernel.org/linux-scsi/20200623111018.31954-1-martin.kepplinger@puri.sm/ Martin Kepplinger (3): scsi: devinfo: add new flag BLIST_MEDIA_CHANGE scsi: sd: send REQUEST SENSE for BLIST_MEDIA_CHANGE devices in runtime_resume() scsi: devinfo: add BLIST_MEDIA_CHANGE for Ultra HS-SD/MMC usb cardreaders drivers/scsi/scsi_devinfo.c | 1 + drivers/scsi/sd.c | 26 +++++++++++++++++++++++++- include/scsi/scsi_devinfo.h | 6 +++--- 3 files changed, 29 insertions(+), 4 deletions(-)