On Thu, Sep 13, 2018 at 03:15:39PM +0300, Adrian Hunter wrote: > On 13/09/18 15:05, Ming Lei wrote: > > On Thu, Sep 13, 2018 at 02:28:48PM +0300, Adrian Hunter wrote: > >> blk-mq does not support runtime pm, so disable blk-mq support for now. > > > > So could you describe a bit what the issue you are trying to fix? > > UFS is a low-power solution, so we must be able to runtime suspend. > > > > > This is host level runtime PM you are trying to address, and if blk-mq > > runtime isn't enabled, I guess the host won't be runtime suspended at all > > because some of its descendant are always active. > > > > So seems we need to do nothing for preventing the host controller from > > entering runtime suspend. > > We don't want to prevent the host controller from runtime suspending, quite > the opposite. OK, got it. However, in previous discussion, it is strongly objected to use per-driver/device .use_blk_mq switch, so not sure if this way can be accepted. BTW, I just posted the runtime PM enablement patches[1] for blk-mq, and I verified that it works fine and passed blktests & xfstest & my other sanity tests, could you try it on UFS? [1] https://marc.info/?l=linux-block&m=153684095523409&w=2 Thanks, Ming
