| Message ID | 20210112093329.3639-1-martin.kepplinger@puri.sm |
|---|---|
| Headers | show |
| Series | scsi: add runtime PM workaround for SD cardreaders | expand |
Am Dienstag, dem 12.01.2021 um 10:33 +0100 schrieb Martin Kepplinger: > revision history > ---------------- > v2: > * move module parameter to sd > * add Documentation > > v1: > https://lore.kernel.org/linux-scsi/20210111152029.28426-1-martin.kepplinger@puri.sm/T/#t > > > > 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 basically always fails. I'd like to discuss a way to fix this > or at least allow users 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/ > > and I sent the first of these patches in August, as a reference: > https://lore.kernel.org/linux-scsi/20200824190400.12339-1-martin.kepplinger@puri.sm/ > so this is where I'm following up on. > > I'm not sure whether maintaining an in-kernel quirk for specific > devices > makes sense so here I suggest adding a userspace knob. This way > there's at > least a chance to use runtime PM for sd cardreaders that send > MEDIA_CHANGED. > > I'd appreciate any feedback. > > Martin Kepplinger (3): > scsi: add expecting_media_change flag to error path > scsi: sd: add ignore_resume_medium_changed disk setting > scsi: sd: Documentation: describe ignore_resume_medium_changed > > Documentation/scsi/sd-parameters.rst | 14 ++++++++ > drivers/scsi/scsi_error.c | 36 +++++++++++++++++--- > drivers/scsi/sd.c | 50 > +++++++++++++++++++++++++++- > drivers/scsi/sd.h | 1 + > include/scsi/scsi_device.h | 1 + > 5 files changed, 96 insertions(+), 6 deletions(-) > hi James, Bart and all, since this is absolutely needed for runtime pm with the SD device we use I assume there are others that would benefit from this too. Do you have any concerns or thoughts about this (logic and interface)? the patches still apply. thanks a lot, martin
On 3/27/21 3:48 AM, Martin Kepplinger wrote: > since this is absolutely needed for runtime pm with the SD device we > use I assume there are others that would benefit from this too. Do you > have any concerns or thoughts about this (logic and interface)? Hi Martin, Since the issue addressed by this patch series concerns a controller bug, please use the SCSI core BLIST mechanism instead of introducing a new sysfs attribute. A sysfs attribute could be misconfigured. BLIST attributes however are set from inside the kernel and hence do not need help from userspace. See e.g. c360652006bb ("scsi: devinfo: BLIST_RETRY_ASC_C1 for Fujitsu ETERNUS"). Thanks, Bart.