Hi, On Fri, Mar 6, 2020 at 4:00 PM Douglas Anderson <dianders@xxxxxxxxxxxx> wrote: > > From trawling through the code (see the "A lot of comments" change) I > found that "tcs_in_use" was only kept up-to-date for ACTIVE_ONLY TCSs. > ...yet tcs_is_free() was checking the variable called from > tcs_invalidate() and tcs_invalidate() is only used for non-ACTIVE_ONLY > TCSs. > > Let's change tcs_invalidate() to just check the "RSC_DRV_STATUS" > register, which was presumably the important part. > > It also feels like for ACTIVE_ONLY TCSs that it probably wasn't > important to check the "RSC_DRV_STATUS". We'll keep doing it just in > case but we'll add a warning if it ever actually mattered. > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > --- > > drivers/soc/qcom/rpmh-rsc.c | 23 +++++++++++++++++++---- > 1 file changed, 19 insertions(+), 4 deletions(-) After other RPMH email threads, it's possible that this patch isn't quite right. ...but also the code wasn't quite right before. Specifically if we have 0 active TCSs then it's possible that we've used a wake TCS to send an active-only request. That would be a case where "tcs_in_use" might be set and we'd need to make sure that tcs_invalidate() checks it. However: 1. We need to add locking to tcs_invalidate() since "tcs_in_use" is protected by drv->lock and tcs_invalidate() didn't grab that lock. 2. We should add documentation explaining the situation. I'm still waiting on overall review / testing of my series, but I'll put it on my list to address this for v2. -Doug
