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[v3,0/4] scsi: add runtime PM workaround for SD cardreaders

Message ID 20210328102531.1114535-1-martin.kepplinger@puri.sm
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Series scsi: add runtime PM workaround for SD cardreaders | expand

Message

Martin Kepplinger March 28, 2021, 10:25 a.m. UTC 
hi,

In short: there are SD cardreaders that send MEDIA_CHANGED on
(runtime) resume. We cannot use runtime PM with these devices as
I/O always fails. I'd like to discuss a way to fix this
or at least allow us to work around this problem:

For the full background, the discussion started in June 2020 here:
https://lore.kernel.org/linux-scsi/20200623111018.31954-1-martin.kepplinger@puri.sm/

I'd appreciate any feedback.

Especially: Any naming-preferences for the flags? And is the specific
device that I need this workaround for (Generic Ultra HS-SD/MMC, connected
via USB) too "generic" maybe? Not sure about what possibilities I'd have here...


revision history
----------------
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

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/


Martin Kepplinger (4):
  scsi: add expecting_media_change flag to error path
  scsi: devinfo: add new flag BLIST_MEDIA_CHANGE
  scsi: sd: use expecting_media_change for BLIST_MEDIA_CHANGE devices
  scsi: devinfo: add BLIST_MEDIA_CHANGE for Ultra HS-SD/MMC usb
    cardreaders

 drivers/scsi/scsi_devinfo.c |  1 +
 drivers/scsi/scsi_error.c   | 36 +++++++++++++++++++++++++++++++-----
 drivers/scsi/sd.c           | 23 ++++++++++++++++++++++-
 include/scsi/scsi_device.h  |  1 +
 include/scsi/scsi_devinfo.h |  6 +++---
 5 files changed, 58 insertions(+), 9 deletions(-)