Adding Kartihik > Subject: Re: [PATCH 06/10] mtd: intel-dg: wake card on operations > > Hi Alexander, > > Please reduce the context when answering, otherwise it's hard to find > all places where you commented. > > >> > > > That's the part that I'm not sure if I agree. if I remember from some > >> > > > experiments in the past, > >> > > > when you call to wake up the child, the parent will wakeup first > anyway. > >> > > > > >> > > The child (mtd device) does not exist at this point of time. > >> > > To create MTD device, the partition table should be provided > >> > > and it read directly from flash that should be powered to do read. > >> > > >> > I don't understand... you have the mtd->dev at this point... this is > >> > the one you should be touching, not the mtd->dev.parent... even at the > >> > probe, but moreover on everywhere else as well. > >> > > >> > >> At the probe time I do not have dev->mtd, but now I see you point here. > >> I'll separate power management: > >> - probe before dev->mtd creation will use aux_dev->dev (that will be mtd- > >> >dev.parent later) > >> - mtd functions will use mtd->dev > >> > >> Is this that you have in mind? > > > > I've tried it and found out that mtd->dev is not initialized if partitions are > present [1]. > > Miquel - this may be the reason why other mtd drivers use pci or platform > > devices to manage runtime pm. > > Or I have missed something? > > Please keep in mind there is _a lot_ of history behind mtd, and > sometimes choices from the past cannot be simply "fixed" without > breaking userspace. The problem with mtd is that the "mtd" structure > defines nothing with precision. It may be a controller, a chip, a > partition, or whatever mix of those. In this particular case, I believe > you are mentioning the KEEP_PARTITIONED_MASTER configuration, which by > default is unset, which means you'll loose the "top level" mtd device? > > However in general I believe the "framework" struct device is maybe less > relevant than the "bus" struct device when it comes to runtime PM, so > actually I would eventually expect this device to be used? > So, we can't reliable use the mtd here and should hook power management on mtd->parent, as done in the patch. Not sure if there any value in extending mtd to support runtime power management. - - Thanks, Sasha > > [1] https://elixir.bootlin.com/linux/v6.12- > rc6/source/drivers/mtd/mtdcore.c#L1078 > > Thanks, > Miquèl
